Novel amido derivatives and their use as positive allosteric modulators of metabotropic glutamate receptors

ABSTRACT

The present invention relates to novel compounds of Formula (I), wherein X 1 , X 2 , X 3 , X 4 , A m  and B n  are defined as in Formula (I); invention compounds are modulators of metabotropic glutamate receptors—subtype 4 (“mGluR4”) which are useful for the treatment or prevention of central nervous system disorders as well as other disorders modulated by mGluR4 receptors. 
     
       
         
         
             
             
         
       
     
     The invention is also directed to pharmaceutical compositions and the use of such compounds in the manufacture of medicaments, as well as to the use of such compounds for the prevention and treatment of such diseases in which mGluR4 is involved.

This application is a continuation of U.S. application Ser. No. 13/135,069, which is a continuation of U.S. application Ser. No. 12/452,601, which is a national stage of international application PCT/EP2008/059043 filed Jul. 10, 2008, which claims the benefit under 35 U.S.C. 119(a) and 365(b) of UK application no. 0713686.4, filed Jul. 13, 2007.

SUMMARY OF THE INVENTION

The present invention relates to novel compounds of Formula (I), wherein X¹, X², X³, X⁴, A^(m) and B^(n) are defined as in Formula (I); invention compounds are modulators of metabotropic glutamate receptors—subtype 4 (“mGluR4”) which are useful for the treatment or prevention of central nervous system disorders as well as other disorders modulated by mGluR4 receptors. The invention is also directed to pharmaceutical compositions and the use of such compounds in the manufacture of medicaments, as well as to the use of such compounds for the prevention and treatment of such diseases in which mGluR4 is involved.

BACKGROUND OF THE INVENTION

Glutamate is the major amino-acid transmitter in the mammalian central nervous system (CNS). Glutamate plays a major role in numerous physiological functions, such as learning and memory but also sensory perception, development of synaptic plasticity, motor control, respiration and regulation of cardiovascular function. Furthermore, glutamate is at the center of several different neurological and psychiatric diseases, where there is an imbalance in glutamatergic neurotransmission.

Glutamate mediates synaptic neurotransmission through the activation of ionotropic glutamate receptor channels (iGluRs), namely the NMDA, AMPA and kainate receptors which are responsible for fast excitatory transmission (Nakanishi et al., (1998) Brain Res Rev., 26:230-235).

In addition, glutamate activates metabotropic glutamate receptors (mGluRs) which have a more modulatory role that contributes to the fine-tuning of synaptic efficacy.

The mGluRs are G protein-coupled receptors (GPCRs) with seven-transmembrane spanning domains and belong to GPCR family 3 along with the calcium-sensing, GABAb and pheromone receptors.

The mGluR family is composed of eight members. They are classified into three groups (group I comprising mGluR1 and mGluR5; group II comprising mGluR2 and mGluR3; group III comprising mGluR4, mGluR6, mGluR7 and mGluR8) according to sequence homology, pharmacological profile and nature of intracellular signalling cascades activated (Schoepp et al. (1999) Neuropharmacology, 38:1431-76).

Glutamate activates the mGluRs through binding to the large extracellular amino-terminal domain of the receptor, herein called the orthosteric binding site. This activation induces a conformational change of the receptor which results in the activation of the G-protein and intracellular signalling pathways.

In the central nervous system, mGluR4 receptors are expressed most intensely in the cerebellar cortex, basal ganglia, sensory relay nuclei of the thalamus and hippocampus (Bradley et al. (1999) Journal of Comparative Neurology, 407:33-46; Corti et al. (2002) Neuroscience, 110:403-420). The mGluR4 subtype is negatively coupled to adenylate cyclase via activation of the Gαi/o protein, is expressed primarily on presynaptic terminals, functioning as an autoreceptor or heteroceptor and activation of mGluR4 leads to decreases in transmitter release from presynaptic terminals (Corti et al. (2002) Neuroscience, 110:403-420; Millan et al. (2002) Journal of Biological Chemistry 277:47796-47803; Valenti et al. (2003) Journal of Neuroscience 23:72218-7226).

Orthosteric agonists of mGluR4 are not selective and activate the other Group III mGluRs (Schoepp et al. (1999) Neuropharmacology 38:1431-1476). The Group III orthosteric agonist L-AP4 was able to reduce motor deficits in animal models of Parkinson's disease (Valenti et al. (2003) J. Neurosci. 23:7218-7226) and decrease excitotoxicity (Bruno et al. (2000) J. Neurosci. 20; 6413-6420) and these effects appear to be mediated through mGluR4 (Marino et al. (2005) Curr. Topics Med. Chem. 5:885-895). In addition to LAP-4, ACPT-1, another selective group III mGluR agonist has been shown to caused a dose-and-structure dependant decrease in haloperidol-induced catalepsy and attenuated haloperidol-increased Proenkephalin mRNA expression in the striatum (Konieczny et al. 2007). Furthermore, Lopez et al. (2007, J Neuroscience) have shown that bilateral infusions of ACPT-I or LAP-4 into the globus pallidus fully reversed the severe akinetic deficits produced by 6-hydroxydopamine lesions of nigrostriatal dopamine neurons in a reaction-time task without affecting the performance of controls. In addition, the reversal of haloperidol-induced catalepsy by intrapallidal ACPT-1 was prevented by concomitant administration of a selective group III receptor antagonist (RS)-alpha-cyclopropyl-4-phosphonophenylglycine. The opposite effects produced by group III mGluR activation in the SNr strongly suggest a role of mGluR4 rather than others mGluR receptor sub-types in normalizing basal ganglia activity (Lopez et al. 2007).

These results suggest that, among mGluRs subtypes, mGluR4 is believed to be the most interesting novel drug target for the treatment of Parkinson's disease (for a review see Conn et al. Nature Review Neuroscience 2005).

Symptoms of Parkinson's disease appear to be due to an imbalance in the direct and indirect output pathways of the basal ganglia and reduction of transmission at the inhibitory GABAergic striato-pallidal synapse in the indirect pathway may result in alleviation of these symptoms (Marino et al. (2002) Amino Acids, 23:185-191).

mGluR4 is more abundant in striato-pallidal synapses than in striato-nigral synapses, and its localization suggests function as a presynaptic heteroceptor on GABAergic neurons (Bradley et al. (1999) Journal of Comparative Neurology, 407:33-46) suggesting that selective activation or positive modulation of mGluR4 would decrease GABA release in this synapse thereby decreasing output of the indirect pathway and reducing or eliminating the Parkinson's disease symptoms.

A new avenue for developing selective compounds acting at mGluRs is to identify molecules that act through allosteric mechanisms, modulating the receptor by binding to a site different from the highly conserved orthosteric binding site.

Positive allosteric modulators of mGluRs have emerged recently as novel pharmacological entities offering this attractive alternative. This type of molecule has been discovered for mGluR1, mGluR2, mGluR4, mGluR5, mGluR7 and mGluR8 (Knoflach F. et al. (2001) Proc. Natl. Acad. Sci. USA., 98:13402-13407; Johnson K et al. (2002) Neuropharmacology, 43:291; O'Brien J. A. et al. (2003) Mol. Pharmacol., 64:731-40; Johnson M. P. et al. (2003) J. Med. Chem., 46:3189-92; Marino M. J. et al. (2003) Proc. Natl. Acad. Sci. USA., 100:13668-73; Mitsukawa K. et al. (2005) Proc Natl Acad Sci USA 102(51):18712-7; Wilson J. et al. (2005) Neuropharmacology 49:278; for a review see Mutel V. (2002) Expert Opin. Ther. Patents, 12:1-8; Kew J. N. (2004) Pharmacol. Ther., 104(3):233-44; Johnson M. P. et al. (2004) Biochem. Soc. Trans., 32:881-7; recently Ritzen A., Mathiesen, J. M., and Thomsen C. (2005) Basic Clin. Pharmacol. Toxicol. 97:202-13).

In particular molecules have been described as mGluR4 positive allosteric modulators (Maj et al. (2003) Neuropharmacology 45:895-906; Mathiesen et al. (2003) British Journal of Pharmacology 138:1026-1030). It has been demonstrated that such molecules have been characterized in in vitro systems as well as in rat brain slices where they potentiated the effect of LAP-4 in inhibiting transmission at the striatopallidal synapse. These compounds do not activate the receptor by themselves (Marino et al. (2003) Proc. Nat. Acad. Sci. USA 100:13668-13673). Rather, they enable the receptor to produce a maximal response to a concentration of glutamate or the Group III orthosteric agonist L-AP4 which by itself induces a minimal response.

PHCCC, a positive allosteric modulator of mGluR4 not active on others mGluRs (Maj et al. (2003) Neuropharmacology 45:895-906), has been shown to be efficacious in animal models of Parkinson's disease thus representing a potential novel therapeutic approach for Parkinson's disease as well as for other motor disorders and disturbances (Marino et al. (2003) Proc. Nat. Acad. Sci. USA 100:13668-13673), neurodegeneration in Parkinson's disease (Marino et al. (2005) Curr. Topics Med. Chem. 5:885-895; Valenti et al. (2005) J. Pharmacol. Exp. Ther. 313:1296-1304; Vernon et al. (2005) Eur. J. Neurosci. 22:1799-1806, Battaglia et al. (2006) J. Neurosci. 26:7222-7229), and neurodegeneration in Alzheimer's disease or due to ischemic or traumatic insult (Maj et al. (2003) Neuropharmacology 45:895-906).

PHCCC also has been shown to be active in animal model of anxiety (Stachowicz et al. (2004) Eur J Pharmacol 498:153-156). Previously, ACPT-1 has been showed to produce a dose-dependent anti-conflict effect after intrahippocampal administration and anti-depressant-like effects in rats after intracerebroventricular administration (Tatarczynska et al., 2002)

Activation of mGluR4 receptors which are expressed in α- and F cells in the islets of Langerhans inhibits glucagon secretion. Molecules which activate or potentiate agonist activity of these receptors may be an effective treatment for hyperglycemia, one of the symptoms of type 2 diabetes (Uehara et al. (2004) Diabetes 53:998-1006).

The β-chemokine RANTES is importantly involved in neuronal inflammation and has been implicated in the pathophysiology of multiple sclerosis. Activation of Group III mGluRs with L-AP4 reduced the synthesis and release RANTES in wild-type cultured astrocytes, whereas the ability of L-AP4 to inhibit RANTES was greatly decreased in astrocyte cultures from mGluR4 knockout mice (Besong et al. (2002) Journal of Neuroscience, 22:5403-5411). These data suggest that positive allosteric modulators of mGluR4 may be an effective treatment for neuroinflammatory disorders of the central nervous system, including multiple sclerosis and related disorders.

Two different variants of the mGluR4 receptor are expressed in taste tissues and may function as receptors for the umami taste sensation (Monastyrskaia et al. (1999) Br. J Pharmacol. 128:1027-1034; Toyono et al. (2002) Arch. Histol. Cytol. 65:91-96). Thus positive allosteric modulators of mGluR4 may be useful as taste agents, flavour agents, flavour enhancing agents or food additives.

There are anatomical evidence that the majority of vagal afferents innervating gastric muscle express group III mGluRs (mGluR4, mGluR6, mGluR7 and mGluR8) and actively transport receptors to their peripheral endings (Page et al (2005) 128:402-10). Recently, it was shown that the activation of peripheral group III mGluRs inhibited vagal afferents mechanosensitivity in vitro which translates into reduced triggering of transient lower oesophagal sphincter relaxations and gastroesophageal reflux in vivo (Young et al (2008) Neuropharmacol 54:965-975). Labelling for mGluR4 and mGluR8 was abundant in gastric vagal afferents in the nodose ganglion, at their termination sites in the nucleus tractus solitarius and in gastric vagal motoneurons. These data suggest that positive allosteric modulators of mGluR4 may be an effective treatment for gastro-esophageal reflux disease (GERD) and lower esophageal disorders and gastro-intestinal disorders.

International patent publication WO2005/007096 describes mGluR4 receptor positive allosteric modulator useful, alone or in combination with a neuroleptic agent, for treating or preventing movement disorders. However, none of the specifically disclosed compounds are structurally related to the compounds of the invention.

-   (i) International patent publications WO2007/072090 and     WO2006/167029 describe respectively thienopyridines as modulators of     mGluR1 and mGluR5 and tricyclic compounds as mGluR1 antagonists. -   (ii) International patent publication WO2007/001975 describes     heterocyclic carboxamides as histamine H3 antagonists. International     patent publication WO2004/087048 describes benzamides as modulators     of metabotropic glutamate receptors. -   (iii) International patent publication WO2006/074884 describes     thiazole-4-carboxamides as mGluR5 receptor antagonists. -   (iv) US patent publications US2006199960 and US2006199828 describe     3-aminopyridine-2-carboxamides and 3-aminopyrazine-2-carboxamides     respectively as metabotropic glutamate receptor antagonists. -   (v) International patent publication WO99/36416 describes     furan-2-carboxamides and thiophen-2-carboxamides as modulators of     metabotropic glutamate receptors.

It has now surprisingly been found that the compounds of general formula I show potent activity and selectivity on mGluR4 receptor. The compounds of the invention demonstrate advantageous properties over compounds of the prior art. Improvements have been observed in one or more of the following characteristics of the compounds of the invention: the potency on the target, the selectivity for the target, the bioavailability, the brain penetration, and the activity in behavioural models.

The present invention relates to a method of treating or preventing a condition in a mammal, including a human, the treatment or prevention of which is affected or facilitated by the neuromodulatory effect of mGluR4 modulators.

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to compounds having metabotropic glutamate receptor 4 modulator activity. In its most general compound aspect, the present invention provides a compound according to Formula (I),

a pharmaceutically acceptable acid or base addition salt thereof, a stereochemically isomeric form thereof and an N-oxide form thereof, wherein: X¹ is selected from the group of N, O and S and X², X³ and X⁴ are each independently selected from the group of C, N, O, S and C═C representing a 5 or 6 membered heteroaryl ring which may further be substituted by 1 to 3 radicals A^(m); m is an integer ranging from 1 to 3; A^(m) radicals are each independently selected from the group of hydrogen, halogen, —CN, —OH, —NO₂, —CF₃, —SH, —NH₂ and an optionally substituted radical selected from the group of —(C₁-C₆)alkyl, —(C₁-C₆)alkylhalo, —(C₃-C₇)cycloalkyl, —(C₁-C₆)alkylcyano, —(C₁-C₆)alkylheteroaryl, —(C₁-C₆)alkylaryl, aryl, heteroaryl, heterocycle, —(C₀-C₆)alkyl-OR¹, —O—(C₂-C₆)alkyl-OR¹, —NR¹—(C₂-C₆)alkyl-OR², —(C₃-C₂)cycloalkyl-(C₁-C₆)alkyl, —O—(C₃-C₇)cycloalkyl-(C₁-C₆)alkyl, —NR¹—(C₃-C₂)cycloalkyl-(C₁-C₆)alkyl, —(C₁-C₆)alkylhalo-OR¹, —(C₁-C₆)alkylhalo-NR¹R², —(C₀-C₆)alkyl-S—R¹, —O—(C₂-C₆)alkyl-S—R¹, —NR¹—(C₂-C₆)alkyl-S—R², —(C₀-C₆)alkyl-S(═O)—R¹, —O—(C₁-C₆)alkyl-S(═O)—R¹, —NR¹—(C₁-C₆)alkyl-S(═O)—R², —(C₀-C₆)alkyl-S(═O)₂—R¹, —O—(C₁-C₆)alkyl-S(═O)₂—R¹, —NR¹—(C₁-C₆)alkyl-S(═O)₂—R², —(C₀-C₆)alkyl-NR¹R², —O—(C₂-C₆)alkyl-NR¹R², —NR¹—(C₂-C₆)alkyl-NR²R³, —(C₀-C₆)alkyl-S(═O)₂NR¹R², —O—(C₁-C₆)alkyl-S(═O)₂NR¹R², —NR¹—(C₁-C₆)alkyl-S(═O)₂NR²R³, —(C₀-C₆)alkyl-NR¹—S(═O)₂R², —O—(C₂-C₆)alkyl-NR¹—S(═O)₂R², —NR¹—(C₂-C₆)alkyl-NR²—S(═O)₂R³, —(C₀-C₆)alkyl-C(═O)—NR¹R², —O—(C₁-C₆)alkyl-C(═O)—NR¹R², —NR¹—(C₁-C₆)alkyl-C(═O)—NR²R³, —(C₀-C₆)alkyl-NR¹C(═O)—R², —O—(C₂-C₆)alkyl-NR¹C(═O)—R², —NR¹—(C₂-C₆)alkyl-NR²C(═O)—R³, —(C₀-C₆)alkyl-OC(═O)—R¹, —O—(C₂-C₆)alkyl-OC(═O)—R¹, —NR¹—(C₂-C₆)alkyl-OC(═O)—R², —(C₀-C₆)alkyl-C(═O)—OR¹, —O—(C₁-C₆)alkyl-C(═O)—OR¹, —NR¹—(C₁-C₆)alkyl-C(═O)—OR², —(C₀-C₆)alkyl-C(═O)—R¹, —O—(C₁-C₆)alkyl-C(═O)—R¹, —NR¹—(C₁-C₆)alkyl-C(═O)—R², —(C₀-C₆)alkyl-NR¹—C(═O)—OR², —(C₀-C₆)alkyl-O—C(═O)—NR¹R², —(C₀-C₆)alkyl-NR¹—C(═NR²)—NR³R⁴, —(C₀-C₆)alkyl-NR¹—C(═O)—NR²R³, —O—(C₂-C₆)alkyl-NR¹—C(═O)—NR²R³, —NR¹—(C₂-C₆)alkyl-NR²—C(═O)—NR³R⁴ and —(C₀-C₆)alkyl-NR¹—C(═S)—NR²R³; Any two radicals of A^(m) (A¹ and A²) may be taken together to form an optionally substituted 3 to 10 membered carbocyclic or heterocyclic ring; R¹, R², R³ and R⁴ are each independently hydrogen or an optionally substituted radical selected from the group of —(C₁-C₆)alkylhalo, —(C₁-C₆)alkyl, —(C₁-C₆)alkylcyano, —(C₃-C₇)cycloalkyl, —(C₄-C₁₀)alkylcycloalkyl, heteroaryl, —(C₁-C₆)alkylheteroaryl, aryl, heterocycle and —(C₁-C₆)alkylaryl; Any two radicals of R (R¹, R², R³ or R⁴) may be taken together to form an optionally substituted 3 to 10 membered carbocyclic or heterocyclic ring; n is an integer ranging from 1 to 3; B^(n) radicals are each independently selected from the group of hydrogen, halogen, —CN, —OH, —NO₂, —CF₃, —SH, —NH₂ and an optionally substituted radical selected from the group of —(C₁-C₆)alkyl, —(C₁-C₆)alkylhalo, —(C₃-C₇)cycloalkyl, —(C₁-C₆)alkylcyano, —(C₁-C₆)alkylheteroaryl, —(C₁-C₆)alkylaryl, aryl, heteroaryl, heterocycle, —(C₀-C₆)alkyl-OR⁵, —O—(C₂-C₆)alkyl-OR⁵, —NR⁵(C₂-C₆)alkyl-OR⁶, —(C₃-C₇)cycloalkyl-(C₁-C₆)alkyl, —O—(C₃-C₇)cycloalkyl-(C₁-C₆)alkyl, —NR⁵—(C₃-C₇)cycloalkyl-(C₁-C₆)alkyl, —(C₁-C₆)alkylhalo-OR⁵, —(C₁-C₆)alkylhalo-NR⁵R⁶, —(C₀-C₆)alkyl-S—R⁵, —O—(C₂-C₆)alkyl-S—R⁵, —NR⁵—(C₂-C₆)alkyl-S—R⁶, —(C₀-C₆)alkyl-S(═O)—R⁵, —O—(C₁-C₆)alkyl-S(═O)—R⁵, —NR⁵—(C₁-C₆)alkyl-S(═O)—R⁶, —(C₀-C₆)alkyl-S(═O)₂—R⁵, —O—(C₁-C₆)alkyl-S(═O)₂—R⁵, —NR⁵—(C₁-C₆)alkyl-S(═O)₂—R⁶, —(C₀-C₆)alkyl-NR⁵R⁶, —O—(C₂-C₆)alkyl-NR⁵R⁶, —NR⁵—(C₂-C₆)alkyl-NR⁶R², —(C₀-C₆)alkyl-S(═O)₂NR⁵R⁶, —O—(C₁-C₆)alkyl-S(═O)₂NR⁵R⁶, —NR⁵—(C₁-C₆)alkyl-S(═O)₂NR⁶R⁷, —(C₀-C₆)alkyl-NR⁵—S(═O)₂R⁶, —O—(C₂-C₆)alkyl-NR⁵—S(═O)₂R⁶, —NR⁵—(C₂-C₆)alkyl-NR⁶—S(═O)₂R⁷, —(C₀-C₆)alkyl-C(═O)—NR⁵R⁶, —O—(C₁-C₆)alkyl-C(═O)—NR⁵R⁶, —NR⁵—(C₁-C₆)alkyl-C(═O)—NR⁶R², —(C₀-C₆)alkyl-NR⁵C(═O)—R⁶, —O—(C₂-C₆)alkyl-NR⁵C(═O)—R⁶, —NR⁵—(C₂-C₆)alkyl-NR⁶C(═O)—R², —(C₀-C₆)alkyl-OC(═O)—R⁵, —O—(C₂-C₆)alkyl-OC(═O)—R⁵, —NR⁵—(C₂-C₆)alkyl-OC(═O)—R⁶, —(C₀-C₆)alkyl-C(═O)—OR⁵, —O—(C₁-C₆)alkyl-C(═O)—OR⁵, —NR⁵—(C₁-C₆)alkyl-C(═O)—OR⁶, —(C₀-C₆)alkyl-C(═O)—R⁵, —O—(C₁-C₆)alkyl-C(═O)—R⁵, —NR⁵—(C₁-C₆)alkyl-C(═O)—R⁶, —(C₀-C₆)alkyl-NR⁵—C(═O)—OR⁶, —(C₀-C₆)alkyl-O—C(═O)—NR⁵R⁶, —(C₀-C₆)alkyl-NR⁵—C(═NR⁶)—NR²R⁸, —(C₀-C₆)alkyl-NR⁵—C(═O)—NR⁶R², —O—(C₂-C₆)alkyl-NR⁵—C(═O)—NR⁶R², —NR⁵—(C₂-C₆)alkyl-NR⁶—C(═O)—NR⁷R⁸ and —(C₀-C₆)alkyl-NR⁵—C(═S)—NR⁶R²; Any two radicals of B^(n) (B¹ and B²) may be taken together to form an optionally substituted 3 to 10 membered carbocyclic or heterocyclic ring; R⁵, R⁶, R⁷ and R⁸ are each independently hydrogen or an optionally substituted radical selected from the group of —(C₁-C₆)alkylhalo, —(C₁-C₆)alkyl, —(C₁-C₆)alkylcyano, —(C₃-C₇)cycloalkyl, —(C₄-C₁₀)alkylcycloalkyl, heteroaryl, —(C₁-C₆)alkylheteroaryl, aryl, heterocycle and —(C₁-C₆)alkylaryl; Any two radicals of R (R⁵, R⁶, R⁷ or R⁸) may be taken together to form an optionally substituted 3 to 10 membered carbocyclic or heterocyclic ring; provided that:

(i) Formula (I)

can not be

and provided that:

(ii) Formula (I)

can not be

when B¹ is NR⁵R⁶ and CH₂NR⁵R⁶; and provided that: (iii) Formula (I)

can not be

and provided that:

(iv) Formula (I)

can not be

and provided that: (v) when X¹ is O or S and X², X³ and X⁴ are C then in Formula (I)

can not be

The compounds thienopyridines known as such from international patent publications WO2007/072090 and WO2006/167029 are excluded from the present invention by virtue of proviso (i).

The compounds heterocyclic carboxamides known as such from international patent publication WO2007/001975 and benzamides known as such from international patent publication WO2004/087048 are excluded from the present invention by virtue of proviso (ii).

The compounds thiazole-4-carboxamides known as such from international patent publication WO2006/074884 are excluded from the present invention by virtue of proviso (iii).

The compounds 3-aminopyridine-2-carboxamides and 3-aminopyrazine-2-carboxamides known respectively as such from US patent publications US2006199960 and US2006199828 are excluded from the present invention by virtue of proviso (iv).

The compounds furan-2-carboxamides and thiophen-2-carboxamides known as such from international patent publication WO99/36416 are excluded from the present invention by virtue of proviso (v).

In one aspect of Formula (I), the invention concerns a compound according to Formula (I-a),

a pharmaceutically acceptable acid or base addition salt thereof, a stereochemically isomeric form thereof and an N-oxide form thereof, wherein: X¹ is selected from the group of N, O and S and X², X³ and X⁴ are each independently selected from the group of C, N, O, S and C═C representing a 5 or 6 membered heteroaryl ring which may further be substituted by 1 to 3 radicals A^(m); m is an integer ranging from 1 to 3; A^(m) radicals are each independently selected from the group of hydrogen, halogen, —CN, —OH, —NO₂, —CF₃, —SH, —NH₂ and an optionally substituted radical selected from the group of —(C₁-C₆)alkyl, —(C₁-C₆)alkylhalo, —(C₃-C₇)cycloalkyl, —(C₁-C₆)alkylcyano, —(C₁-C₆)alkylheteroaryl, —(C₁-C₆)alkylaryl, aryl, heteroaryl, heterocycle, —(C₀-C₆)alkyl-OR¹, —O—(C₂-C₆)alkyl-OR¹, —NR¹(C₂-C₆)alkyl-OR², —(C₃-C₂)cycloalkyl-(C₁-C₆)alkyl, —O—(C₃-C₂)cycloalkyl-(C₁-C₆)alkyl, —NR¹—(C₃-C₂)cycloalkyl-(C₁-C₆)alkyl, —(C₁-C₆)alkylhalo-OR¹, —(C₁-C₆)alkylhalo-NR¹R², —(C₀-C₆)alkyl-S—R¹, —O—(C₂-C₆)alkyl-S—R¹, —NR¹—(C₂-C₆)alkyl-S—R², —(C₀-C₆)alkyl-S(═O)—R¹, —O—(C₁-C₆)alkyl-S(═O)—R¹, —NR¹—(C₁-C₆)alkyl-S(═O)—R², —(C₀-C₆)alkyl-S(═O)₂—R¹, —O—(C₁-C₆)alkyl-S(═O)₂—R¹, —NR¹—(C₁-C₆)alkyl-S(═O)₂—R², —(C₀-C₆)alkyl-NR¹R², —O—(C₂-C₆)alkyl-NR¹R², —NR¹—(C₂-C₆)alkyl-NR²R³, —(C₀-C₆)alkyl-S(═O)₂NR¹R², —O—(C₁-C₆)alkyl-S(═O)₂NR¹R², —NR¹—(C₁-C₆)alkyl-S(═O)₂NR²R³, —(C₀-C₆)alkyl-NR¹—S(═O)₂R², —O—(C₂-C₆)alkyl-NR¹—S(═O)₂R², —NR¹—(C₂-C₆)alkyl-NR²—S(═O)₂R³, —(C₀-C₆)alkyl-C(═O)—NR¹R², —O—(C₁-C₆)alkyl-C(═O)—NR¹R², —NR¹—(C₁-C₆)alkyl-C(═O)—NR²R³, —(C₀-C₆)alkyl-NR¹C(═O)—R², —O—(C₂-C₆)alkyl-NR¹C(═O)—R², —NR¹—(C₂-C₆)alkyl-NR²C(═O)—R³, —(C₀-C₆)alkyl-OC(═O)—R¹, —O—(C₂-C₆)alkyl-OC(═O)—R¹, —NR¹—(C₂-C₆)alkyl-OC(═O)—R², —(C₀-C₆)alkyl-C(═O)—OR¹, —O—(C₁-C₆)alkyl-C(═O)—OR¹, —NR¹—(C₁-C₆)alkyl-C(═O)—OR², —(C₀-C₆)alkyl-C(═O)—R¹, —O—(C₁-C₆)alkyl-C(═O)—R¹, —NR¹—(C₁-C₆)alkyl-C(═O)—R², —(C₀-C₆)alkyl-NR¹—C(═O)—OR², —(C₀-C₆)alkyl-O—C(═O)—NR¹R², —(C₀-C₆)alkyl-NR¹—C(═NR²)—NR³R⁴, —(C₀-C₆)alkyl-NR¹—C(═O)—NR²R³, —O—(C₂-C₆)alkyl-NR¹—C(═O)—NR²R³, —NR¹—(C₂-C₆)alkyl-NR²—C(═O)—NR³R⁴ and —(C₀-C₆)alkyl-NR¹—C(═S)—NR²R³; Any two radicals of A^(m) (A¹ and A²) may be taken together to form an optionally substituted 3 to 10 membered carbocyclic or heterocyclic ring; R¹, R², R³ and R⁴ are each independently hydrogen or an optionally substituted radical selected from the group of —(C₁-C₆)alkylhalo, —(C₁-C₆)alkyl, —(C₁-C₆)alkylcyano, —(C₃-C₇)cycloalkyl, —(C₄-C₁₀)alkylcycloalkyl, heteroaryl, —(C₁-C₆)alkylheteroaryl, aryl, heterocycle and —(C₁-C₆)alkylaryl; Any two radicals of R(R¹, R², R³ or R⁴) may be taken together to form an optionally substituted 3 to 10 membered carbocyclic or heterocyclic ring; B¹ and B² are each independently selected from the group of hydrogen, halogen, —CN, —OH, —NO₂, —CF₃, —SH, —NH₂ and an optionally substituted radical selected from the group of —(C₁-C₆)alkyl, —(C₁-C₆)alkylhalo, —(C₃-C₇)cycloalkyl, —(C₁-C₆)alkylcyano, —(C₁-C₆)alkylheteroaryl, —(C₁-C₆)alkylaryl, aryl, heteroaryl, heterocycle, —(C₀-C₆)alkyl-OR⁵, —O—(C₂-C₆)alkyl-OR⁵, —NR⁵(C₂-C₆)alkyl-OR⁶, —(C₃-C₇)cycloalkyl-(C₁-C₆)alkyl, —O—(C₃-C₇)cycloalkyl-(C₁-C₆)alkyl, —NR⁵—(C₃-C₇)cycloalkyl-(C₁-C₆)alkyl, —(C₁-C₆)alkylhalo-OR⁵, —(C₁-C₆)alkylhalo-NR⁵R⁶, —(C₀-C₆)alkyl-S—R⁵, —O—(C₂-C₆)alkyl-S—R⁵, —NR⁵—(C₂-C₆)alkyl-S—R⁶, —(C₀-C₆)alkyl-S(═O)—R⁵, —O—(C₁-C₆)alkyl-S(═O)—R⁵, —NR⁵—(C₁-C₆)alkyl-S(═O)—R⁶, —(C₀-C₆)alkyl-S(═O)₂—R⁵, —O—(C₁-C₆)alkyl-S(═O)₂—R⁵, —NR⁵—(C₁-C₆)alkyl-S(═O)₂—R⁶, —(C₀-C₆)alkyl-NR⁵R⁶, —O—(C₂-C₆)alkyl-NR⁵R⁶, —NR⁵—(C₂-C₆)alkyl-NR⁶R⁷, —(C₀-C₆)alkyl-S(═O)₂NR⁵R⁶, —O—(C₁-C₆)alkyl-S(═O)₂NR⁵R⁶, —NR⁵—(C₁-C₆)alkyl-S(═O)₂NR⁶R⁷, —(C₀-C₆)alkyl-NR⁵—S(═O)₂R⁶, —O—(C₂-C₆)alkyl-NR⁵—S(═O)₂R⁶, —NR⁵—(C₂-C₆)alkyl-NR⁶—S(═O)₂R⁷, —(C₀-C₆)alkyl-C(═O)—NR⁵R⁶, —O—(C₁-C₆)alkyl-C(═O)—NR⁵R⁶, —NR⁵—(C₁-C₆)alkyl-C(═O)—NR⁶R⁷, —(C₀-C₆)alkyl-NR⁵C(═O)—R⁶, —O—(C₂-C₆)alkyl-NR⁵C(═O)—R⁶, —NR⁵—(C₂-C₆)alkyl-NR⁶C(═O)—R⁷, —(C₀-C₆)alkyl-OC(═O)—R⁵, —O—(C₂-C₆)alkyl-OC(═O)—R⁵, —NR⁵—(C₂-C₆)alkyl-OC(═O)—R⁶, —(C₀-C₆)alkyl-C(═O)—OR⁵, —O—(C₁-C₆)alkyl-C(═O)—OR⁵, —NR⁵—(C₁-C₆)alkyl-C(═O)—OR⁶, —(C₀-C₆)alkyl-C(═O)—R⁵, —O—(C₁-C₆)alkyl-C(═O)—R⁵, —NR⁵—(C₁-C₆)alkyl-C(═O)—R⁶, —(C₀-C₆)alkyl-NR⁵—C(═O)—OR⁶, —(C₀-C₆)alkyl-O—C(═O)—NR⁵R⁶, —(C₀-C₆)alkyl-NR⁵—C(═NR⁶)—NR⁷R⁸, —(C₀-C₆)alkyl-NR⁵—C(═O)—NR⁶R⁷, —O—(C₂-C₆)alkyl-NR⁵—C(═O)—NR⁶R⁷, —NR⁵—(C₂-C₆)alkyl-NR⁶—C(═O)—NR⁷R⁸ and —(C₀-C₆)alkyl-NR⁵—C(═S)—NR⁶R⁷; Any two radicals of B^(n) (B¹ and B²) may be taken together to form an optionally substituted 3 to 10 membered carbocyclic or heterocyclic ring; R⁵, R⁶, R⁷ and R⁸ are each independently hydrogen or an optionally substituted radical selected from the group of —(C₁-C₆)alkylhalo, —(C₁-C₆)alkyl, —(C₁-C₆)alkylcyano, —(C₃-C₇)cycloalkyl, —(C₄-C₁₀)alkylcycloalkyl, heteroaryl, —(C₁-C₆)alkylheteroaryl, aryl, heterocycle and —(C₁-C₆)alkylaryl; Any two radicals of R(R⁵, R⁶, R⁷ or R⁸) may be taken together to form an optionally substituted 3 to 10 membered carbocyclic or heterocyclic ring; provided that according to proviso (i):

Formula (I)

can not be

and provided that according to proviso (iii):

Formula (I)

can not be

and provided that according to proviso (iv):

Formula (I)

can not be

and provided that according to proviso (v): when X¹ is O or S and X², X³ and X⁴ are C then in Formula (I)

can not be

In a second aspect of Formula (I), the invention concerns a compound according to Formula (I-b),

a pharmaceutically acceptable acid or base addition salt thereof, a stereochemically isomeric form thereof and an N-oxide form thereof, wherein: X¹ is selected from the group of N, O and S and X², X³ and X⁴ are each independently selected from the group of C, N, O, S and C═C representing a 5 or 6 membered heteroaryl ring which may further be substituted by 1 to 3 radicals A^(m); m is an integer ranging from 1 to 3; A^(m) radicals are each independently selected from the group of hydrogen, halogen, —CN, —OH, —NO₂, —CF₃, —SH, —NH₂ and an optionally substituted radical selected from the group of —(C₁-C₆)alkyl, —(C₁-C₆)alkylhalo, —(C₃-C₇)cycloalkyl, —(C₁-C₆)alkylcyano, —(C₁-C₆)alkylheteroaryl, —(C₁-C₆)alkylaryl, aryl, heteroaryl, heterocycle, —(C₀-C₆)alkyl-OR¹, —O—(C₂-C₆)alkyl-OR¹, —NR¹(C₂-C₆)alkyl-OR², —(C₃-C₇)cycloalkyl-(C₁-C₆)alkyl, —O—(C₃-C₇)cycloalkyl-(C₁-C₆)alkyl, —NR¹—(C₃-C₇)cycloalkyl-(C₁-C₆)alkyl, —(C₁-C₆)alkylhalo-OR¹, —(C₁-C₆)alkylhalo-NR¹R², —(C₀-C₆)alkyl-S—R¹, —O—(C₂-C₆)alkyl-S—R¹, —NR¹—(C₂-C₆)alkyl-S—R², —(C₀-C₆)alkyl-S(═O)—R¹, —O—(C₁-C₆)alkyl-S(═O)—R¹, —NR¹—(C₁-C₆)alkyl-S(═O)—R², —(C₀-C₆)alkyl-S(═O)₂—R¹, —O—(C₁-C₆)alkyl-S(═O)₂—R¹, —NR¹—(C₁-C₆)alkyl-S(═O)₂—R², —(C₀-C₆)alkyl-NR¹R², —O—(C₂-C₆)alkyl-NR¹R², —NR¹—(C₂-C₆)alkyl-NR²R³, —(C₀-C₆)alkyl-S(═O)₂NR¹R², —O—(C₁-C₆)alkyl-S(═O)₂NR¹R², —NR¹—(C₁-C₆)alkyl-S(═O)₂NR²R³, —(C₀-C₆)alkyl-NR¹—S(═O)₂R², —O—(C₂-C₆)alkyl-NR¹—S(═O)₂R², —NR¹—(C₂-C₆)alkyl-NR²—S(═O)₂R³, —(C₀-C₆)alkyl-C(═O)—NR¹R², —O—(C₁-C₆)alkyl-C(═O)—NR¹R², —NR¹—(C₁-C₆)alkyl-C(═O)—NR²R³, —(C₀-C₆)alkyl-NR¹C(═O)—R², —O—(C₂-C₆)alkyl-NR¹C(═O)—R², —NR¹—(C₂-C₆)alkyl-NR²C(═O)—R³, —(C₀-C₆)alkyl-OC(═O)—R¹, —O—(C₂-C₆)alkyl-OC(═O)—R¹, —NR¹—(C₂-C₆)alkyl-OC(═O)—R², —(C₀-C₆)alkyl-C(═O)—OR¹, —O—(C₁-C₆)alkyl-C(═O)—OR¹, —NR¹—(C₁-C₆)alkyl-C(═O)—OR², —(C₀-C₆)alkyl-C(═O)—R¹, —O—(C₁-C₆)alkyl-C(═O)—R¹, —NR¹—(C₁-C₆)alkyl-C(═O)—R², —(C₀-C₆)alkyl-NR¹—C(═O)—OR², —(C₀-C₆)alkyl-O—C(═O)—NR¹R², —(C₀-C₆)alkyl-NR¹—C(═NR²)—NR³R⁴, —(C₀-C₆)alkyl-NR¹—C(═O)—NR²R³, —O—(C₂-C₆)alkyl-NR¹—C(═O)—NR²R³, —NR¹—(C₂-C₆)alkyl-NR²—C(═O)—NR³R⁴ and —(C₀-C₆)alkyl-NR¹—C(═S)—NR²R³; Any two radicals of A^(m) (A¹ and A²) may be taken together to form an optionally substituted 3 to 10 membered carbocyclic or heterocyclic ring; R¹, R², R³ and R⁴ are each independently hydrogen or an optionally substituted radical selected from the group of —(C₁-C₆)alkylhalo, —(C₁-C₆)alkyl, —(C₁-C₆)alkylcyano, —(C₃-C₇)cycloalkyl, —(C₄-C₁₀)alkylcycloalkyl, heteroaryl, —(C₁-C₆)alkylheteroaryl, aryl, heterocycle and —(C₁-C₆)alkylaryl; Any two radicals of R(R¹, R², R³ or R⁴) may be taken together to form an optionally substituted 3 to 10 membered carbocyclic or heterocyclic ring; B¹ and B² are each independently selected from the group of hydrogen, halogen, —CN, —OH, —NO₂, —CF₃, —SH, —NH₂ and an optionally substituted radical selected from the group of —(C₁-C₆)alkyl, —(C₁-C₆)alkylhalo, —(C₃-C₇)cycloalkyl, —(C₁-C₆)alkylcyano, —(C₁-C₆)alkylheteroaryl, —(C₁-C₆)alkylaryl, aryl, heteroaryl, heterocycle, —(C₀-C₆)alkyl-OR⁵, —O—(C₂-C₆)alkyl-OR⁵, —NR⁵(C₂-C₆)alkyl-OR⁶, —(C₃-C₇)cycloalkyl-(C₁-C₆)alkyl, —O—(C₃-C₇)cycloalkyl-(C₁-C₆)alkyl, —NR⁵—(C₃-C₇)cycloalkyl-(C₁-C₆)alkyl, —(C₁-C₆)alkylhalo-OR⁵, —(C₁-C₆)alkylhalo-NR⁵R⁶, —(C₀-C₆)alkyl-S—R⁵, —O—(C₂-C₆)alkyl-S—R⁵, —NR⁵—(C₂-C₆)alkyl-S—R⁶, —(C₀-C₆)alkyl-S(═O)—R⁵, —O—(C₁-C₆)alkyl-S(═O)—R⁵, —NR⁵—(C₁-C₆)alkyl-S(═O)—R⁶, —(C₀-C₆)alkyl-S(═O)₂—R⁵, —O—(C₁-C₆)alkyl-S(═O)₂—R⁵, —NR⁵—(C₁-C₆)alkyl-S(═O)₂—R⁶, —(C₀-C₆)alkyl-NR⁵R⁶, —O—(C₂-C₆)alkyl-NR⁵R⁶, —NR⁵—(C₂-C₆)alkyl-NR⁶R², —(C₀-C₆)alkyl-S(═O)₂NR⁵R⁶, —O—(C₁-C₆)alkyl-S(═O)₂NR⁵R⁶, —NR⁵—(C₁-C₆)alkyl-S(═O)₂NR⁶R², —(C₀-C₆)alkyl-NR⁵—S(═O)₂R⁶, —O—(C₂-C₆)alkyl-NR⁵—S(═O)₂R⁶, —NR⁵—(C₂-C₆)alkyl-NR⁶—S(═O)₂R⁷, —(C₀-C₆)alkyl-C(═O)—NR⁵R⁶, —O—(C₁-C₆)alkyl-C(═O)—NR⁵R⁶, —NR⁵—(C₁-C₆)alkyl-C(═O)—NR⁶R², —(C₀-C₆)alkyl-NR⁵C(═O)—R⁶, —O—(C₂-C₆)alkyl-NR⁵C(═O)—R⁶, —NR⁵—(C₂-C₆)alkyl-NR⁶C(═O)—R², —(C₀-C₆)alkyl-OC(═O)—R⁵, —O—(C₂-C₆)alkyl-OC(═O)—R⁵, —NR⁵—(C₂-C₆)alkyl-OC(═O)—R⁶, —(C₀-C₆)alkyl-C(═O)—OR⁵, —O—(C₁-C₆)alkyl-C(═O)—OR⁵, —NR⁵—(C₁-C₆)alkyl-C(═O)—OR⁶, —(C₀-C₆)alkyl-C(═O)—R⁵, —O—(C₁-C₆)alkyl-C(═O)—R⁵, —NR⁵—(C₁-C₆)alkyl-C(═O)—R⁶, —(C₀-C₆)alkyl-NR⁵—C(═O)—OR⁶, —(C₀-C₆)alkyl-O—C(═O)—NR⁵R⁶, —(C₀-C₆)alkyl-NR⁵—C(═NR⁶)—NR²R⁸, —(C₀-C₆)alkyl-NR⁵—C(═O)—NR⁶R², —O—(C₂-C₆)alkyl-NR⁵—C(═O)—NR⁶R², —NR⁵—(C₂-C₆)alkyl-NR⁶—C(═O)—NR⁷R⁸ and —(C₀-C₆)alkyl-NR⁵—C(═S)—NR⁶R²; Any two radicals of B^(n) (B¹ and B²) may be taken together to form an optionally substituted 3 to 10 membered carbocyclic or heterocyclic ring; R⁵, R⁶, R⁷ and R⁸ are each independently hydrogen or an optionally substituted radical selected from the group of —(C₁-C₆)alkylhalo, —(C₁-C₆)alkyl, —(C₁-C₆)alkylcyano, —(C₃-C₂)cycloalkyl, —(C₄-C₁₀)alkylcycloalkyl, heteroaryl, —(C₁-C₆)alkylheteroaryl, aryl, heterocycle and —(C₁-C₆)alkylaryl; Any two radicals of R(R⁵, R⁶, R⁷ or R⁸) may be taken together to form an optionally substituted 3 to 10 membered carbocyclic or heterocyclic ring; provided that according to proviso (i):

Formula (I)

can not be

and provided that according to proviso (iii):

Formula (I)

can not be

and provided that according to proviso (iv):

Formula (I)

can not be

In a third aspect of Formula (I), the invention concerns a compound according to Formula (I-c),

a pharmaceutically acceptable acid or base addition salt thereof, a stereochemically isomeric form thereof and an N-oxide form thereof, wherein: X¹ is selected from the group of N, O and S and X², X³ and X⁴ are each independently selected from the group of C, N, O, S and C═C representing a 5 or 6 membered heteroaryl ring which may further be substituted by 1 to 3 radicals A^(m); m is an integer ranging from 1 to 3; A^(m) radicals are each independently selected from the group of hydrogen, halogen, —CN, —OH, —NO₂, —CF₃, —SH, —NH₂ and an optionally substituted radical selected from the group of —(C₁-C₆)alkyl, —(C₁-C₆)alkylhalo, —(C₃-C₇)cycloalkyl, —(C₁-C₆)alkylcyano, —(C₁-C₆)alkylheteroaryl, —(C₁-C₆)alkylaryl, aryl, heteroaryl, heterocycle, —(C₀-C₆)alkyl-OR¹, —O—(C₂-C₆)alkyl-OR¹, —NR¹(C₂-C₆)alkyl-OR², —(C₃-C₂)cycloalkyl-(C₁-C₆)alkyl, —O—(C₃-C₂)cycloalkyl-(C₁-C₆)alkyl, —NR¹—(C₃-C₂)cycloalkyl-(C₁-C₆)alkyl, —(C₁-C₆)alkylhalo-OR¹, —(C₁-C₆)alkylhalo-NR¹R², —(C₀-C₆)alkyl-S—R¹, —O—(C₂-C₆)alkyl-S—R¹, —NR¹—(C₂-C₆)alkyl-S—R², —(C₀-C₆)alkyl-S(═O)—R¹, —O—(C₁-C₆)alkyl-S(═O)—R¹, —NR¹—(C₁-C₆)alkyl-S(═O)—R², —(C₀-C₆)alkyl-S(═O)₂—R¹, —O—(C₁-C₆)alkyl-S(═O)₂—R¹, —NR¹—(C₁-C₆)alkyl-S(═O)₂—R², —(C₀-C₆)alkyl-NR¹R², —O—(C₂-C₆)alkyl-NR¹R², —NR¹—(C₂-C₆)alkyl-NR²R³, —(C₀-C₆)alkyl-S(═O)₂NR¹R², —O—(C₁-C₆)alkyl-S(═O)₂NR¹R², —NR¹—(C₁-C₆)alkyl-S(═O)₂NR²R³, —(C₀-C₆)alkyl-NR¹—S(═O)₂R², —O—(C₂-C₆)alkyl-NR¹—S(═O)₂R², —NR¹—(C₂-C₆)alkyl-NR²—S(═O)₂R³, —(C₀-C₆)alkyl-C(═O)—NR¹R², —O—(C₁-C₆)alkyl-C(═O)—NR¹R², —NR¹—(C₁-C₆)alkyl-C(═O)—NR²R³, —(C₀-C₆)alkyl-NR¹C(═O)—R², —O—(C₂-C₆)alkyl-NR¹C(═O)—R², —NR¹—(C₂-C₆)alkyl-NR²C(═O)—R³, —(C₀-C₆)alkyl-OC(═O)—R¹, —O—(C₂-C₆)alkyl-OC(═O)—R¹, —NR¹—(C₂-C₆)alkyl-OC(═O)—R², —(C₀-C₆)alkyl-C(═O)—OR¹, —O—(C₁-C₆)alkyl-C(═O)—OR¹, —NR¹—(C₁-C₆)alkyl-C(═O)—OR², —(C₀-C₆)alkyl-C(═O)—R¹, —O—(C₁-C₆)alkyl-C(═O)—R¹, —NR¹—(C₁-C₆)alkyl-C(═O)—R², —(C₀-C₆)alkyl-NR¹—C(═O)—OR², —(C₀-C₆)alkyl-O—C(═O)—NR¹R², —(C₀-C₆)alkyl-NR¹—C(═NR²)—NR³R⁴, —(C₀-C₆)alkyl-NR¹—C(═O)—NR²R³, —O—(C₂-C₆)alkyl-NR¹—C(═O)—NR²R³, —NR¹—(C₂-C₆)alkyl-NR²—C(═O)—NR³R⁴ and —(C₀-C₆)alkyl-NR¹—C(═S)—NR²R³; Any two radicals of A^(m) (A¹ and A²) may be taken together to form an optionally substituted 3 to 10 membered carbocyclic or heterocyclic ring; R¹, R², R³ and R⁴ are each independently hydrogen or an optionally substituted radical selected from the group of —(C₁-C₆)alkylhalo, —(C₁-C₆)alkyl, —(C₁-C₆)alkylcyano, —(C₃-C₂)cycloalkyl, —(C₄-C₁₀)alkylcycloalkyl, heteroaryl, —(C₁-C₆)alkylheteroaryl, aryl, heterocycle and —(C₁-C₆)alkylaryl; Any two radicals of R(R¹, R², R³ or R⁴) may be taken together to form an optionally substituted 3 to 10 membered carbocyclic or heterocyclic ring; B¹ is selected from the group of hydrogen, halogen, —CN, —OH, —NO₂, —CF₃, —SH, —NH₂ and an optionally substituted radical selected from the group of —(C₁-C₆)alkyl, —(C₁-C₆)alkylhalo, —(C₃-C₇)cycloalkyl, —(C₁-C₆)alkylcyano, —(C₁-C₆)alkylheteroaryl, —(C₁-C₆)alkylaryl, aryl, heteroaryl, heterocycle, —(C₀-C₆)alkyl-OR⁵, —O—(C₂-C₆)alkyl-OR⁵, —NR⁵(C₂-C₆)alkyl-OR⁶, —(C₃-C₇)cycloalkyl-(C₁-C₆)alkyl, —O—(C₃-C₂)cycloalkyl-(C₁-C₆)alkyl, —NR⁵—(C₃-C₂)cycloalkyl-(C₁-C₆)alkyl, —(C₁-C₆)alkylhalo-OR⁵, —(C₁-C₆)alkylhalo-NR⁵R⁶, —(C₀-C₆)alkyl-S—R⁵, —O—(C₂-C₆)alkyl-S—R⁵, —NR⁵—(C₂-C₆)alkyl-S—R⁶, —(C₀-C₆)alkyl-S(═O)—R⁵, —O—(C₁-C₆)alkyl-S(═O)—R⁵, —NR⁵—(C₁-C₆)alkyl-S(═O)—R⁶, —(C₀-C₆)alkyl-S(═O)₂—R⁵, —O—(C₁-C₆)alkyl-S(═O)₂—R⁵, —NR⁵—(C₁-C₆)alkyl-S(═O)₂—R⁶, —(C₀-C₆)alkyl-NR⁵R⁶, —O—(C₂-C₆)alkyl-NR⁵R⁶, —NR⁵—(C₂-C₆)alkyl-NR⁶R⁷, —(C₀-C₆)alkyl-S(═O)₂NR⁵R⁶, —O—(C₁-C₆)alkyl-S(═O)₂NR⁵R⁶, —NR⁵—(C₁-C₆)alkyl-S(═O)₂NR⁶R⁷, —(C₀-C₆)alkyl-NR⁵—S(═O)₂R⁶, —O—(C₂-C₆)alkyl-NR⁵—S(═O)₂R⁶, —NR⁵—(C₂-C₆)alkyl-NR⁶—S(═O)₂R⁷, —(C₀-C₆)alkyl-C(═O)—NR⁵R⁶, —O—(C₁-C₆)alkyl-C(═O)—NR⁵R⁶, —NR⁵—(C₁-C₆)alkyl-C(═O)—NR⁶R⁷, —(C₀-C₆)alkyl-NR⁵C(═O)—R⁶, —O—(C₂-C₆)alkyl-NR⁵C(═O)—R⁶, —NR⁵—(C₂-C₆)alkyl-NR⁶C(═O)—R⁷, —(C₀-C₆)alkyl-OC(═O)—R⁵, —O—(C₂-C₆)alkyl-OC(═O)—R⁵, —NR⁵—(C₂-C₆)alkyl-OC(═O)—R⁶, —(C₀-C₆)alkyl-C(═O)—OR⁵, —O—(C₁-C₆)alkyl-C(═O)—OR⁵, —NR⁵—(C₁-C₆)alkyl-C(═O)—OR⁶, —(C₀-C₆)alkyl-C(═O)—R⁵, —O—(C₁-C₆)alkyl-C(═O)—R⁵, —NR⁵—(C₁-C₆)alkyl-C(═O)—R⁶, —(C₀-C₆)alkyl-NR⁵—C(═O)—OR⁶, —(C₀-C₆)alkyl-O—C(═O)—NR⁵R⁶, —(C₀-C₆)alkyl-NR⁵—C(═NR⁶)—NR⁷R⁸, —(C₀-C₆)alkyl-NR⁵—C(═O)—NR⁶R⁷, —O—(C₂-C₆)alkyl-NR⁵—C(═O)—NR⁶R⁷, —NR⁵—(C₂-C₆)alkyl-NR⁶—C(═O)—NR⁷R⁸ and —(C₀-C₆)alkyl-NR⁵—C(═S)—NR⁶R⁷; R⁵, R⁶, R⁷ and R⁸ are each independently hydrogen or an optionally substituted radical selected from the group of —(C₁-C₆)alkylhalo, —(C₁-C₆)alkyl, —(C₁-C₆)alkylcyano, —(C₃-C₇)cycloalkyl, —(C₄-C₁₀)alkylcycloalkyl, heteroaryl, —(C₁-C₆)alkylheteroaryl, aryl, heterocycle and —(C₁-C₆)alkylaryl; Any two radicals of R(R⁵, R⁶, R⁷ or R⁸) may be taken together to form an optionally substituted 3 to 10 membered carbocyclic or heterocyclic ring; Z is selected from the group of O and NR⁹; and R⁹ is hydrogen or an optionally substituted radical selected from the group of —(C₁-C₆)alkylhalo, —(C₁-C₆)alkyl, —(C₁-C₆)alkylcyano, —(C₃-C₇)cycloalkyl, —(C₄-C₁₀)alkylcycloalkyl, heteroaryl, —(C₁-C₆)alkylheteroaryl, aryl, heterocycle, —C(═O)alkyl, —C(═O)—(C₃-C₇)cycloalkyl —C(═O)aryl, —C(═O)heteroaryl, —C(═O)heterocycle, —C(═O)—(C₁-C₆)alkylcycloalkyl, —C(═O)—(C₁-C₆)alkylheteroaryl and —(C₁-C₆)alkylaryl.

Particular preferred compounds of the invention are compounds as mentioned in the following list (List of Particular Preferred Compounds), as well as a pharmaceutically acceptable acid or base addition salt thereof, a stereochemically isomeric form thereof and an N-oxide form thereof.

-   N-(3,4-dichlorophenyl)-1H-pyrrole-2-carboxamide -   N-(3-Chlorophenyl)-1H-imidazole-2-carboxamide -   N-(3-Methoxyphenyl)thiophene-2-carboxamide -   5-Methyl-N-(4-phenoxyphenyl)furan-2-carboxamide -   Furan-2-carboxylic acid     {3-[2-(4-fluoro-phenyl)-2-oxo-ethoxy]-phenyl}-amide -   N-(3-Methoxyphenyl)picolinamide -   N-(3-Methoxyphenyl)-2-methylthiazole-4-carboxamide -   N-(3-Chlorophenyl)thiophene-2-carboxamide -   5-Bromo-N-(3-methoxyphenyl)furan-2-carboxamide -   N-(3-Chlorophenyl)picolinamide -   N-(3-Methoxyphenyl)thiazole-2-carboxamide -   N-(3-(2-(3-Methoxyphenyl)-2-oxoethoxy)phenyl)furan-2-carboxamide -   N-(3-(2-oxo-2-p-tolylethoxy)phenyl)furan-2-carboxamide -   N-(3-(2-(4-Methoxyphenyl)-2-oxoethoxy)phenyl)furan-2-carboxamide -   N-(3-(1-Oxo-1-p-tolylpropan-2-yloxy)phenyl)furan-2-carboxamide -   N-(3-(Trifluoromethoxy)phenyl)picolinamide -   N-(3-(2-(3-Chlorophenyl)-2-oxoethoxy)phenyl)picolinamide -   N-(3-(3-Phenylpropoxy)phenyl)picolinamide -   N-(3-(2-(2-Methoxyphenyl)-2-oxoethoxy)phenyl)picolinamide -   N-(3-(2-(3-Methoxyphenyl)-2-oxoethoxy)phenyl)picolinamide -   N-(3-(2-(3-Fluorophenyl)-2-oxoethoxy)phenyl)picolinamide -   N-(3-(2-(2-Chlorophenyl)-2-oxoethoxy)phenyl)picolinamide -   N-(3-Fluorophenyl)picolinamide -   N-(3-Methoxyphenyl)-5-methylisoxazole-3-carboxamide -   N-(4-Fluoro-3-methoxyphenyl)picolinamide -   N-(3-Chlorophenyl)-1H-pyrrole-2-carboxamide -   N-(3-(2-(2-Fluorophenyl)-2-oxoethoxy)phenyl)picolinamide -   N-(3-Methoxyphenyl)pyrimidine-4-carboxamide -   6-Fluoro-N-(4-fluoro-3-methoxyphenyl)picolinamide -   N-(3-Chloro-4-(pyrimidin-2-yloxy)phenyl)picolinamide -   N-(4-Fluoro-3-methoxyphenyl)thiazole-2-carboxamide -   N-(3-Chloro-4-(pyrimidin-2-yloxy)phenyl)-2-methylthiazole-4-carboxamide -   N-(3-Chloro-4-(pyrimidin-2-yloxy)phenyl)thiazole-2-carboxamide -   N-(3-Chloro-4-morpholinophenyl)picolinamide -   N-(3-Chloro-4-(pyridin-2-yloxy)phenyl)picolinamide -   N-(3-Chloro-4-(2,5-difluorophenoxy)phenyl)picolinamide -   N-(3-Chloro-4-(2-chlorophenoxy)phenyl)picolinamide -   N-(3-Chloro-4-(5-(trifluoromethyl)pyridin-2-yloxy)phenyl)picolinamide -   N-(3-Chloro-4-(4-isobutyrylpiperazin-1-yl)phenyl)picolinamide -   N-(3-Methoxy-4-(pyrimidin-2-yloxy)phenyl)picolinamide -   N-(4-(Trifluoromethoxy)phenyl)picolinamide -   N-(3-Chloro-4-(3-chlorophenoxy)phenyl)picolinamide -   N-(3-Chloro-4-(3-fluorophenoxy)phenyl)picolinamide -   N-(3-Chloro-4-(4-fluorophenoxy)phenyl)picolinamide -   N-(3-Chloro-4-(4-chlorophenoxy)phenyl)picolinamide -   N-(3-Chloro-4-(4-propionylpiperazin-1-yl)phenyl)picolinamide -   N-(4-(4-Benzoylpiperazin-1-yl)-3-chlorophenyl)picolinamide -   N-(3-Chloro-4-(4-cyanophenoxy)phenyl)picolinamide -   N-(3-Chloro-4-(3-cyanopyridin-2-yloxy)phenyl)picolinamide -   N-(4-(4-Benzylpiperazin-1-yl)-3-chlorophenyl)picolinamide

DEFINITION OF TERMS

Listed below are definitions of various terms used in the specification and claims to describe the present invention.

For the avoidance of doubt it is to be understood that in this specification “(C₁-C₆)” means a carbon radical having 1, 2, 3, 4, 5 or 6 carbon atoms. “(C₀-C₆)” means a carbon radical having 0, 1, 2, 3, 4, 5 or 6 carbon atoms. In this specification “C” means a carbon atom, “N” means a nitrogen atom, “O” means an oxygen atom and “S” means a sulphur atom.

In the case where a subscript is the integer 0 (zero) the radical to which the subscript refers, indicates that the radical is absent, i.e. there is a direct bond between the radicals.

In this specification, unless stated otherwise, the term “bond” refers to a saturated covalent bond. When two or more bonds are adjacent to one another, they are assumed to be equal to one bond. For example, a radical -A-B-, wherein both A and B may be a bond, the radical is depicting a single bond.

In this specification, unless stated otherwise, the term “alkyl” includes both straight and branched chain alkyl radicals and may be methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl, n-pentyl, i-pentyl, t-pentyl, neo-pentyl, n-hexyl, i-hexyl or t-hexyl. The term “(C₀-C₃)alkyl” refers to an alkyl radical having 0, 1, 2 or 3 carbon atoms and may be methyl, ethyl, n-propyl and i-propyl.

In this specification, unless stated otherwise, the term “cycloalkyl” refers to an optionally substituted carbocycle containing no heteroatoms, including mono-, bi-, and tricyclic saturated carbocycles, as well as fused ring systems. Such fused ring systems can include one ring that is partially or fully unsaturated such as a benzene ring to form fused ring systems such as benzo-fused carbocycles. Cycloalkyl includes such fused ring systems as spirofused ring systems. Examples of cycloalkyl include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, decahydronaphthalene, adamantane, indanyl, fluorenyl and 1,2,3,4-tetrahydronaphthalene and the like. The term “(C₃-C₇)cycloalkyl” may be cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and the like.

The term “aryl” refers to an optionally substituted monocyclic or bicyclic hydrocarbon ring system containing at least one unsaturated aromatic ring. Examples and suitable values of the term “aryl” are phenyl, naphthyl, 1,2,3,4-tetrahydronaphthyl, indyl, indenyl and the like.

In this specification, unless stated otherwise, the term “heteroaryl” refers to an optionally substituted monocyclic or bicyclic unsaturated, aromatic ring system containing at least one heteroatom selected independently from N, O or S. Examples of “heteroaryl” may be, but are not limited to thienyl, pyridyl, thiazolyl, isothiazolyl, furyl, pyrrolyl, triazolyl, imidazolyl, oxadiazolyl, oxazolyl, isoxazolyl, pyrazolyl, imidazolonyl, oxazolonyl, thiazolonyl, tetrazolyl, thiadiazolyl, benzoimidazolyl, benzooxazolyl, benzothiazolyl, tetrahydrotriazolopyridyl, tetrahydrotriazolopyrimidinyl, benzofuryl, benzothiophenyl, thionaphthyl, indolyl, isoindolyl, pyridonyl, pyridazinyl, pyrazinyl, pyrimidinyl, quinolyl, phtalazinyl, naphthyridinyl, quinoxalinyl, quinazolyl, imidazopyridyl, oxazolopyridyl, thiazolopyridyl, imidazopyridazinyl, oxazolopyridazinyl, thiazolopyridazinyl, cynnolyl, pteridinyl, furazanyl, benzotriazolyl, pyrazolopyridinyl and purinyl.

In this specification, unless stated otherwise, the term “alkylaryl”, “alkylheteroaryl” and “alkylcycloalkyl” refers respectively to a substituent that is attached via the alkyl radical to an aryl, heteroaryl or cycloalkyl radical, respectively. The term “(C₁-C₆)alkylaryl” includes aryl-C₁-C₆-alkyl radicals such as benzyl, 1-phenylethyl, 2-phenylethyl, 1-phenylpropyl, 2-phenylpropyl, 3-phenylpropyl, 1-naphthylmethyl and 2-naphthylmethyl. The term “(C₁-C₆)alkyheteroaryl” includes heteroaryl-C₁-C₆-alkyl radicals, wherein examples of heteroaryl are the same as those illustrated in the above definition, such as 2-furylmethyl, 3-furylmethyl, 2-thienylmethyl, 3-thienylmethyl, 1-imidazolylmethyl, 2-imidazolylmethyl, 3-imidazolylmethyl, 2-oxazolylmethyl, 3-oxazolylmethyl, 2-thiazolylmethyl, 3-thiazolylmethyl, 2-pyridylmethyl, 3-pyridylmethyl, 4-pyridylmethyl, 1-quinolylmethyl or the like.

In this specification, unless stated otherwise, the term “heterocycle” refers to an optionally substituted, monocyclic or bicyclic saturated, partially saturated or unsaturated ring system containing at least one heteroatom selected independently from N, O and S.

In this specification, unless stated otherwise, a 5- or 6-membered ring containing one or more atoms independently selected from C, N, O and S, includes aromatic and heteroaromatic rings as well as carbocyclic and heterocyclic rings which may be saturated or unsaturated. Examples of such rings may be, but are not limited to, furyl, isoxazolyl, isothiazolyl, oxazolyl, pyrazinyl, pyrazolyl, pyridazinyl, pyridyl, pyrimidyl, pyrrolyl, thiazolyl, thienyl, imidazolyl, imidazolidinyl, imidazolinyl, triazolyl, morpholinyl, piperazinyl, piperidyl, piperidonyl, pyrazolidinyl, pyrazolinyl, pyrrolidinyl, pyrrolinyl, tetrahydropyranyl, tetrahydrothiopyranyl, oxazolidinonyl, thiomorpholinyl, oxadiazolyl, thiadiazolyl, tetrazolyl, phenyl, cyclohexyl, cyclopentyl, cyclohexenyl and cyclopentenyl.

In this specification, unless stated otherwise, a 3- to 10-membered ring containing one or more atoms independently selected from C, N, O and S, includes aromatic and heteroaromatic rings as well as carbocyclic and heterocyclic rings which may be saturated or unsaturated. Examples of such rings may be, but are not limited to imidazolidinyl, imidazolinyl, morpholinyl, piperazinyl, piperidyl, piperidonyl, pyrazolidinyl, pyrazolinyl, pyrrolidinyl, pyrrolinyl, tetrahydropyranyl, thiomorpholinyl, tetrahydrothiopyranyl, furyl, pyrrolyl, isoxazolyl, isothiazolyl, oxazolyl, oxazolidinonyl, pyrazinyl, pyrazolyl, pyridazinyl, pyridyl, pyrimidyl, pyrrolyl, thiazolyl, thienyl, imidazolyl, triazolyl, phenyl, cyclopropyl, aziridinyl, cyclobutyl, azetidinyl, oxadiazolyl, thiadiazolyl, tetrazolyl, cyclopentyl, cyclopentenyl, cyclohexyl, cyclohexenyl, cycloheptyl, cycloheptenyl, cyclooctyl and cyclooctenyl.

In this specification, unless stated otherwise, the term “halo” or “halogen” may be fluoro, chloro, bromo or iodo.

In this specification, unless stated otherwise, the term “alkylhalo” means an alkyl radical as defined above, substituted with one or more halo radicals. The term “(C₁-C₆)alkylhalo” may include, but is not limited to, fluoromethyl, difluoromethyl, trifluoromethyl, fluoroethyl and difluoroethyl. The term “O—C₁-C₆-alkylhalo” may include, but is not limited to, fluoromethoxy, difluoromethoxy, trifluoromethoxy and fluoroethoxy.

In this specification, unless stated otherwise, the term “alkylcyano” means an alkyl radical as defined above, substituted with one or more cyano.

In this specification, unless stated otherwise, the term “optionally substituted” refers to radicals further bearing one or more substituents which may be, but are not limited to, (C₁-C₆)alkyl, hydroxy, (C₁-C₆)alkyloxy, mercapto, aryl, heterocycle, halogen, trifluoromethyl, pentafluoroethyl, cyano, cyanomethyl, nitro, amino, amido, amidinyl, carboxyl, carboxamide, (C₁-C₆)alkyloxycarbonyl, carbamate, sulfonamide, ester and sulfonyl.

In this specification, unless stated otherwise, the term “solvate” refers to a complex of variable stoichiometry formed by a solute (e.g. a compound of Formula (I)) and a solvent. The solvent is a pharmaceutically acceptable solvent as preferably water; such solvent may not interfere with the biological activity of the solute.

In this specification, unless stated otherwise, the term “positive allosteric modulator of mGluR4” or “allosteric modulator of mGluR4” refers also to a pharmaceutically acceptable acid or base addition salt thereof, a stereochemically isomeric form thereof and an N-oxide form thereof.

Pharmaceutical Compositions

Allosteric modulators of mGluR4 described herein, and the pharmaceutically acceptable salts, solvates and hydrates thereof can be used in pharmaceutical preparations in combination with a pharmaceutically acceptable carrier or diluent. Suitable pharmaceutically acceptable carriers include inert solid fillers or diluents and sterile aqueous or organic solutions. The allosteric modulators of mGluR4 will be present in such pharmaceutical compositions in amounts sufficient to provide the desired dosage amount in the range described herein. Techniques for formulation and administration of the compounds of the instant invention can be found in Remington: the Science and Practice of Pharmacy, 19^(th) edition, Mack Publishing Co., Easton, Pa. (1995).

The amount of allosteric modulators of mGluR4, administered to the subject will depend on the type and severity of the disease or condition and on the characteristics of the subject, such as general health, age, sex, body weight and tolerance to drugs. The skilled artisan will be able to determine appropriate dosages depending on these and other factors. Effective dosages for commonly used CNS drugs are well known to the skilled person. The total daily dose usually ranges from about 0.05-2000 mg.

The present invention relates to pharmaceutical compositions which provide from about 0.01 to 1000 mg of the active ingredient per unit dose. The compositions may be administered by any suitable route. For example orally in the form of capsules, etc. . . . , parenterally in the form of solutions for injection, topically in the form of onguents or lotions, ocularly in the form of eye-drops, rectally in the form of suppositories, intranasally or transcutaneously in the form of delivery system like patches.

For oral administration, the allosteric modulators of mGluR4 thereof can be combined with a suitable solid or liquid carrier or diluent to form capsules, tablets, pills, powders, syrups, solutions, suspensions and the like.

The tablets, pills, capsules, and the like contain from about 0.01 to about 99 weight percent of the active ingredient and a binder such as gum tragacanth, acacias, corn starch or gelatin; excipients such as dicalcium phosphate; a disintegrating agent such as corn starch, potato starch, alginic acid, a lubricant such as magnesium stearate; and a sweetening agent such as sucrose, lactose or saccharin. When a dosage unit form is a capsule, it may contain, in addition to materials of the above type, a liquid carrier such as a fatty oil.

Various other materials may be present as coatings or to modify the physical form of the dosage unit. For instance, tablets may be coated with shellac, sugar or both. A syrup or elixir may contain, in addition to the active ingredient, sucrose as a sweetening agent, methyl and propylparabens as preservatives, a dye and a flavoring such as cherry or orange flavor.

For parenteral administration the disclosed allosteric modulators of mGluR4 can be combined with sterile aqueous or organic media to form injectable solutions or suspensions. For example, solutions in sesame or peanut oil, aqueous propylene glycol and the like can be used, as well as aqueous solutions of water-soluble pharmaceutically-acceptable salts of the compounds. Dispersions can also be prepared in glycerol, liquid polyethylene glycols and mixtures thereof in oils. Under ordinary conditions of storage and use, these preparations contain a preservative to prevent the growth of microorganisms.

In addition, to the formulations described previously, the compounds may also be formulated as a depot preparation. Such long acting formulations may be administered by implantation, for example, subcutaneously or intramuscularly or by intramuscular injection. Thus, for example, as an emulsion in an acceptable oil, or ion exchange resins, or as sparingly soluble derivatives, for example, as sparingly soluble salts.

Preferably disclosed allosteric modulators of mGluR4 or pharmaceutical formulations containing these compounds are in unit dosage form for administration to a mammal. The unit dosage form can be any unit dosage form known in the art including, for example, a capsule, an IV bag, a tablet, or a vial. The quantity of active ingredient in a unit dose of composition is an effective amount and may be varied according to the particular treatment involved. It may be appreciated that it may be necessary to make routine variations to the dosage depending on the age and condition of the patient. The dosage will also depend on the route of administration which may be by a variety of routes including oral, aerosol, rectal, transdermal, subcutaneous, intravenous, intramuscular, intraperitoneal and intranasal.

Methods of Synthesis

The compounds according to the invention, in particular the compounds according to the Formula (I), (I-a), (I-b), (I-c) and (I-d), may be prepared by methods known in the art of organic synthesis as set forth in part by the following synthesis schemes. In all of the schemes described below, it is well understood that protecting groups for sensitive or reactive groups are employed where necessary in accordance with general principles of chemistry. Protecting groups are manipulated according to standard methods of organic synthesis (Green T. W. and Wuts P. G. M. (1991) Protecting Groups in Organic Synthesis, John Wiley & Sons). These groups are removed at a convenient stage of the compound synthesis using methods that are readily apparent to those skilled in the art. The selection of process as well as the reaction conditions and order of their execution shall be consistent with the preparation of compounds of Formula (I), (I-a), (I-b), (I-c) and (I-d).

The compounds according to the invention may be represented as a mixture of enantiomers, which may be resolved into the individual pure R- or S-enantiomers. If for instance, a particular enantiomer is required, it may be prepared by asymmetric synthesis or by derivation with a chiral auxiliary, where the resulting diastereomeric mixture is separated and the auxiliary group cleaved to provide the pure desired enantiomers. Alternatively, where the molecule contains a basic functional group such as an amino or an acidic functional group such as carboxyl, this resolution may be conveniently performed by fractional crystallization from various solvents as the salts of an optical active acid or by other methods known in the literature (e.g. chiral column chromatography).

Resolution of the final product, an intermediate or a starting material may be performed by any suitable method known in the art (Eliel E. L., Wilen S. H. and Mander L. N. (1984) Stereochemistry of Organic Compounds, Wiley-Interscience).

Many of the heterocyclic compounds of the invention can be prepared using synthetic routes well known in the art (Katrizky A. R. and. Rees C. W. (1984) Comprehensive Heterocyclic Chemistry, Pergamon Press).

The product from the reaction can be isolated and purified employing standard techniques, such as extraction, chromatography, crystallization and distillation.

The compounds of the invention may be prepared by general route of synthesis as disclosed in the following methods.

In one embodiment of the present invention compounds of Formula (I) may be prepared according to the synthetic sequences illustrated in Scheme 1. Acid chloride g1 can be generated from carboxylic acid g3 in the presence of a reagent such as thionyl chloride or oxalyl chloride. Then g1 may be coupled with the primary amine g2 in the presence of a base such as Et₃N or DIEA in a suitable solvent.

Amide g4 can also be obtained from the reaction of carboxylic acid g3 and the primary amine g2 (Scheme 1). The reaction may be promoted by a coupling agent known in the art of organic synthesis such as EDCI (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide), in a suitable solvent (e.g. THF, DCM, DMF). Typically, a co-catalyst such as HOBT (hydroxybenzotriazole) will also be present in the reaction mixture. The reaction typically proceeds at ambient temperature for a time in the range of about 4 up to 12 hours.

For a person skilled in the art of organic chemistry it is well understood that amide g5 can be alkylated using either B²X (where X is Cl, Br or I) in the presence of a base such as K₂CO₃, Cs₂CO₃ or NaH in a suitable solvent such as acetone, DMF or THF to yield g6 (Scheme 2).

In another embodiment of the present invention compounds of Formula (I-b) may be prepared according to the synthetic sequences illustrated in Scheme 3. p-Nitro-phenoxy g11 can be obtained from substitution on fluorophenyl g7 by hydroxyl compounds like g8 or by p-nitrophenol g9 on bromide compounds g10 in the presence of a base such as Cs₂CO₃. Then compound g11 can be reduced in the presence of iron or zinc in acetic acid to yield the primary amine g12. Finally, g12 can then be coupled to acid chloride as exemplified earlier in Scheme 1.

In another embodiment of the present invention compounds of Formula (I-c) may be prepared according to the synthetic sequences illustrated in Scheme 4. Piperazine g14 can be acylated under standard conditions in the presence of acid chloride. Then compound g16 can be reduced under standard hydrogenation conditions with Pt/C in primary amine g17. Finally, g17 can then be coupled to acid chloride as exemplified earlier in Scheme 1.

In another embodiment of the present invention compounds of Formula (I-c) may be prepared according to the synthetic sequences illustrated in Scheme 5. Piperazine g14 can be protected by (Boc)₂O, then reduced with Pt/C and coupled with acid chloride under conditions well known for a person skilled in the art. After deprotection under acidic conditions, the secondary amine g22 can finally be acylated either by acid chloride or carboxylic acid as exemplified earlier in Scheme 1.

EXPERIMENTAL

Unless otherwise noted, all starting materials were obtained from commercial suppliers and used without further purification.

Specifically, the following abbreviations may be used in the examples and throughout the specification.

ACN (Acetonitrile) M (Molar) AcOEt (Ethyl acetate) mg (Milligrams) (Boc)₂O (Di-tert-butyl carbonate) MgSO₄ (Magnesium sulphate) Cs₂CO₃ (Cesium carbonate) μL (Microliters) DCM (Dichloromethane) mL (Milliliters) DIEA (Diisopropyl ethyl amine) mmol (Millimoles) DMAP (N,N-Dimethylaminopyridine) M.p. (Melting point) EDCI.HCl (1-3(Dimethylaminopropy1)-3- NaCl (Sodium chloride) ethylcarbodiimide, hydrochloride) Et₃N (Triethylamine) NaHCO₃ (Sodium hydrogenocarbonate) Et₂O (Diethyl ether) NaOH (Sodium hydroxide) EtOH (Ethanol) Pt/C (Platinum on charcoal) HCl (Hydrochloric acid) THF (Tetrahydrofuran) K₂CO₃ (Potassium carbonate) TLC (Thin layer chromatography) LCMS (Liquid Chromatography Mass Spectrum) RT (Retention Time)

All references to brine refer to a saturated aqueous solution of NaCl. Unless otherwise indicated, all temperatures are expressed in ° C. (degrees Centigrade). All reactions are conducted not under an inert atmosphere at room temperature unless otherwise noted.

Most of the reaction were monitored by thin-layer chromatography on 0.25 mm Merck silica gel plates (60F-254), visualized with UV light. Flash column chromatography was performed on prepacked silica gel cartridges (15-40 μM, Merck).

Melting point determination was performed on a Buchi B-540 apparatus.

Examples Example 1 N-(3-Methoxyphenyl)thiophene-2-carboxamide (Final Compound 2-1) Thiophene-2-carbonyl chloride

According to Scheme 1 Step 1: Thiophene-2-carboxylic acid (31.2 mmol, 4.00 g) was slowly added to a solution of thionyl chloride (56.2 mmol, 4.08 mL). The reaction mixture was stirred at room temperature for 1 hour. After evaporation of the thionyl chloride, the crude product was purified by bulb-to-bulb distillation (85° C., 14 Torr) to yield thiophene-2-carbonyl chloride (23.7 mmol, 3.48 g, 76%) as a colorless liquid.

N-(3-methoxyphenyl)thiophene-2-carboxamide

According to Scheme 1 Method A: A solution of thiophene-2-carbonyl chloride (2.92 mmol, 0.31 mL) in DCM (1 mL) was added to solution of 3-methoxyaniline (2.44 mmol, 0.27 mL) and DIEA (4.87 mmol, 0.87 mL) in DCM (4 mL) at 0° C. The reaction mixture was stirred at room temperature for 1 hour. The organic phase was washed with HCl 1 M solution, then with a saturated solution of NaHCO₃, was dried over MgSO₄, was filtered and was concentrated under reduced pressure to yield N-(3-methoxyphenyl)thiophene-2-carboxamide (1.71 mmol, 0.40 g, 70%) as a white solid.

M.p.: 139-145° C.;

LC (Zorbax SB-C₁₈, 3.5 μm, 4.6×30 mm Column) RT=3.80 min; MS m/z ES⁺=234.

Example 2 N-(3-Methoxyphenyl)picolinamide (Final Compound 2-3)

According to Scheme 1 Method B: 3-Methoxyaniline (1.62 mmol, 0.18 mL) was added to a solution of picolinic acid (1.62 mmol, 0.20 g), EDCI.HCl (2.44 mmol, 0.47 g), Et₃N (3.25 mmol, 0.45 mL), hydroxybenzotriazole (1.95 mmol, 0.30 g) in DCM (6 mL) at room temperature. The reaction mixture was stirred at 50° C. for 12 hours. The organic phase was washed with a saturated solution of NaHCO₃ and with brine, was dried over MgSO₄, was filtered and was concentrated under reduced pressure. The crude product was purified by flash chromatography over silica gel using cyclohexane/AcOEt (90:10) as eluent to afford N-(3-methoxyphenyl)picolinamide (1.46 mmol, 0.33 g, 90%) as an orange liquid.

LC (Zorbax SB-C₁₈, 3.5 μm, 4.6×30 mm Column) RT=3.94 min; MS m/z ES⁺=229.

Example 3 N-(3-(2-(2-Methoxyphenyl)-2-oxoethoxy)phenyl)picolinamide (Final Compound 2-9) N-(3-Hydroxyphenyl)picolinamide

According to Example 2: The title compound was prepared from 3-aminophenol (18.0 mmol, 2.00 g). Reaction conditions: 12 hours at 50° C. 1.7 g (7.9 mmol, 43%) of N-(3-hydroxyphenyl)picolinamide were obtained.

LC (Zorbax SB-C₁₈, 3.5 μm, 4.6×30 mm Column) RT=1.74 min; MS m/z ES⁺=215.

N-(3-(2-(2-Methoxyphenyl)-2-oxoethoxy)phenyl)picolinamide

According to Scheme 2: K₂CO₃ (2.33 mmol, 323 mg) and 2-bromo-1-(2-methoxyphenyl)ethanone (0.47 mmol, 107 mg) were added sequentially to a solution of N-(3-hydroxyphenyl)picolinamide (0.47 mmol, 100 mg) in acetone (3 mL). The reaction mixture was stirred at 50° C. for 14 hours. After filtration and evaporation, the crude product was diluted with water and with DCM. The organic phase was washed with brine, was dried over MgSO₄, was filtered and was concentrated under reduced pressure. The crude product was triturated with Et₂O to obtain N-(3-(2-(2-methoxyphenyl)-2-oxoethoxy)phenyl)picolinamide (0.26 mmol, 94 mg, 55%) as a yellow solid.

M.p.: 136-137° C.;

LC (Zorbax SB-C₁₈, 3.5 μm, 4.6×30 mm Column) RT=2.67 min; MS m/z ES⁺=363.

Example 4 N-(3-Chloro-4-(3-chlorophenoxy)phenyl)picolinamide (Final Compound 3-11) 2-Chloro-1-(3-chlorophenoxy)-4-nitrobenzene

According to Scheme 3 Step 1, Method A: 2-Chloro-1-fluoro-4-nitrobenzene (1.12 mmol, 0.20 g) was added to a suspension of 3-chlorophenol (1.02 mmol, 0.10 mL), Cs₂CO₃ (1.25 mmol, 407 mg) in DMF/ACN (40:60, 3.6 mL). The reaction mixture was stirred at room temperature overnight. The reaction mixture was quenched with water. The aqueous phase was extracted with AcOEt. The organic phase was washed with brine, was dried over MgSO₄, was filtered and was concentrated under reduced pressure. The crude product was used without further purification to obtain 2-chloro-1-(3-chlorophenoxy)-4-nitrobenzene (1.02 mmol, 288 mg, 100%) as an orange solid.

LC (Zorbax SB-C₁₈, 3.5 μm, 4.6×30 mm Column) RT=3.22 min.

3-Chloro-4-(3-chlorophenoxy)aniline

According to Scheme 3 Step 2: A suspension of iron (5.07 mmol, 283 mg), acetic acid (1.22 mmol, 70 μL) and of 2-chloro-1-(3-chlorophenoxy)-4-nitrobenzene (1.02 mmol, 288 mg) in water/EtOH (1:1, 8 mL) was stirred at 80° C. for 30 minutes. After evaporation of EtOH, the aqueous phase was basified with a saturated solution of NaHCO₃ and was extracted with AcOEt. The organic phase was washed with brine, was dried over MgSO₄, was filtered and was concentrated under reduced pressure to yield 3-chloro-4-(3-chlorophenoxy)aniline (1.02 mmol, 258 mg, 100%) as a solid. The product was used without further purification.

LC (Zorbax SB-C₁₈, 3.5 μm, 4.6×30 mm Column) RT=2.77 min; MS m/z ES⁺=254.

N-(3-Chloro-4-(3-chlorophenoxy)phenyl)picolinamide

According to Scheme 3 Step 3: Picolinoyl chloride hydrochloride (1.52 mmol, 271 mg) and Et₃N (3.05 mmol, 0.42 mL) were added sequentially to a solution of 3-chloro-4-(3-chlorophenoxy)aniline (1.02 mmol, 258 mg) in DCM (6 mL) at 0° C. The reaction mixture was stirred at room temperature for 2 hours. The organic phase was washed with a saturated solution of NaHCO₃ and with brine, was dried over MgSO₄, was filtered and was concentrated under reduced pressure. The crude product was purified by flash chromatography over silica gel using cyclohexane/AcOEt (90:10) as eluent to afford N-(3-chloro-4-(3-chlorophenoxy)phenyl)picolinamide (0.52 mmol, 187 mg, 51%) as a white solid.

M.p.: 91.5-93.5° C.;

LC (Zorbax SB-C₁₈, 3.5 μm, 4.6×30 mm Column) RT=2.45 min; MS m/z ES⁺=357.

Example 5 N-(3-Methoxy-4-(pyrimidin-2-yloxy)phenyl)picolinamide (Final Compound 3-9) 2-(2-Methoxy-4-nitrophenoxy)pyrimidine

According to Scheme 3 Step 1 Method B: 2-Bromopyrimidine (1.26 mmol, 211 mg) was added to a suspension of 2-methoxy-4-nitrophenol (1.15 mmol, 200 mg), Cs₂CO₃ (1.41 mmol, 460 mg) in DMF (3 mL). The reaction mixture was stirred at 80° C. for 3 days. The reaction mixture was quenched with water. The aqueous phase was extracted with AcOEt. The organic phase was washed with brine, was dried over MgSO₄, was filtered and was concentrated under reduced pressure. The crude product was washed with a solution of NaOH 3M and dried to obtain 2-(2-methoxy-4-nitrophenoxy)pyrimidine (0.89 mmol, 220 mg, 78%) as a solid. The product was used without further purification.

LC (Zorbax SB-C₁₈, 3.5 μm, 4.6×30 mm Column) RT=1.89 min; MS m/z ES⁺=248.

3-Methoxy-4-(pyrimidin-2-yloxy)aniline

According to Scheme 3 Step 2: A suspension of iron (4.45 mmol, 248 mg), acetic acid (1.07 mmol, 61 μL) and of 2-(2-methoxy-4-nitrophenoxy)pyrimidine (0.89 mmol, 220 mg) in water/EtOH (1:1, 7 mL) was stirred at 80° C. for 30 minutes. After evaporation of EtOH, the aqueous phase was basified with a saturated solution of NaHCO₃ and was extracted with AcOEt. The organic phase was washed with brine, was dried over MgSO₄, was filtered and was concentrated under reduced pressure to yield 3-methoxy-4-(pyrimidin-2-yloxy)aniline (0.89 mmol, 193 mg, 100%) as an oil. The product was used without further purification.

LC (Zorbax SB-C₁₈, 3.5 μm, 4.6×30 mm Column) RT=0.56 min; MS m/z ES⁺=218.

N-(3-Methoxy-4-(pyrimidin-2-yloxy)phenyl)picolinamide

According to Scheme 3 Step 3: Picolinoyl chloride hydrochloride (1.33 mmol, 256 mg) and Et₃N (2.67 mmol, 0.37 mL) were added sequentially to a solution of 3-methoxy-4-(pyrimidin-2-yloxy)aniline (0.89 mmol, 193 mg) in DCM (3 mL) at 0° C. The reaction mixture was stirred at room temperature for 2 hours. The organic phase was washed with a saturated solution of NaHCO₃. The aqueous phase was extracted with AcOEt. The organic phase was washed with brine, was dried over MgSO₄, was filtered and was concentrated under reduced pressure. The crude product was purified by flash chromatography over C₁₈ column using water/ACN (70:30) as eluent to afford N-(3-methoxy-4-(pyrimidin-2-yloxy)phenyl)picolinamide (0.17 mmol, 55 mg, 19%) as a white solid.

M.p.: 203-205° C.;

LC (Zorbax SB-C₁₈, 3.5 μm, 4.6×30 mm Column) RT=1.87 min; MS m/z ES⁺=323.

Example 6 N-(3-Chloro-4-(4-isobutyrylpiperazin-1-yl)phenyl)picolinamide (Final Compound 4-2) 1-(4-(2-Chloro-4-nitrophenyl)piperazin-1-yl)-2-methylpropan-1-one

According to Scheme 4 Step 1: Isobutyryl chloride (1.24 mmol, 0.13 mL) and Et₃N (2.48 mmol, 0.35 mL) were added to a solution of 1-(2-chloro-4-nitrophenyl)piperazine (0.83 mmol, 200 mg) in DCM (5 mL) at 0° C. The reaction mixture was stirred at room temperature for 2 hours. The organic phase was washed with a saturated solution of NaHCO₃. The aqueous phase was extracted with AcOEt. The organic phase was washed with brine, was dried over Na₂SO₄, was filtered and was concentrated under reduced pressure to afford 1-(4-(2-chloro-4-nitrophenyl)piperazin-1-yl)-2-methylpropan-1-one (0.83 mmol, 261 mg, 100%). The product was used without further purification.

LC (Zorbax SB-C₁₈, 3.5 μm, 4.6×30 mm Column) RT=2.48 min; MS m/z ES⁺=312.

1-(4-(4-Amino-2-chlorophenyl)piperazin-1-yl)-2-methylpropan-1-one

According to Scheme 4 Step 2: A solution of 1-(4-(2-chloro-4-nitrophenyl)piperazin-1-yl)-2-methylpropan-1-one (0.62 mmol, 195 mg) in EtOH (120 mL) was passed through a Pt/C₅% column in an H-Cube equipment (mode: Full). Then the solution was concentrated under reduced pressure to yield 1-(4-(4-amino-2-chlorophenyl)piperazin-1-yl)-2-methylpropan-1-one (0.62 mmol, 175 mg, 99%). The product was used without further purification.

LC (Zorbax SB-C₁₈, 3.5 μm, 4.6×30 mm Column) RT=1.56 min; MS m/z ES⁺=282.

N-(3-Chloro-4-(4-isobutyrylpiperazin-1-yl)phenyl)picolinamide

According to Scheme 4 Step 3: Picolinoyl chloride hydrochloride (0.93 mmol, 178 mg) and Et₃N (1.86 mmol, 0.26 mL) were added to a solution of 1-(4-(4-amino-2-chlorophenyl)piperazin-1-yl)-2-methylpropan-1-one (0.62 mmol, 175 mg) in DCM (3 mL) at 0° C. The reaction mixture was stirred at room temperature for 2 hours. The organic phase was washed with a saturated solution of NaHCO₃. The aqueous phase was extracted with AcOEt. The organic phase was washed with brine, was dried over Na₂SO₄, was filtered and was concentrated under reduced pressure. The crude product was purified by flash chromatography over C₁₈ column using water/ACN (60:40) as eluent to afford N-(3-chloro-4-(4-isobutyrylpiperazin-1-yl)phenyl)picolinamide (0.11 mmol, 42 mg, 18%) as a white solid.

M.p.: 156-158° C.;

LC (Zorbax SB-C₁₈, 3.5 μm, 4.6×30 mm Column) RT=2.50 min; MS m/z ES⁺=387.

Example 7 N-(3-Chloro-4-(4-propionylpiperazin-1-yl)phenyl)picolinamide (Final Compound 4-3) tert-Butyl 4-(2-chloro-4-nitrophenyl)piperazine-1-carboxylate

According to Scheme 5 Step 1: A solution of 1-(2-chloro-4-nitrophenyl)piperazine (2.90 mmol, 700 mg), Boc₂O (3.19 mmol, 0.96 mL), Et₃N (3.48 mmol, 0.49 mL) and of DMAP (0.29 mmol, 35 mg) in DCM (5 mL) was stirred at room temperature overnight. The organic phase was washed once with HCl 0.1 M, once with water, once with brine, was dried over Na₂SO₄, was filtered and was concentrated under reduced pressure to afford tert-butyl 4-(2-chloro-4-nitrophenyl)piperazine-1-carboxylate (2.50 mmol, 854 mg, 86%). The product was used without further purification.

LC (Zorbax SB-C₁₈, 3.5 μm, 4.6×30 mm Column) RT=3.19 min; MS m/z ES⁺=342.

tert-Butyl 4-(4-amino-2-chlorophenyl)piperazine-1-carboxylate

According to Scheme 5 Step 2: A solution of tert-butyl 4-(2-chloro-4-nitrophenyl)piperazine-1-carboxylate (2.50 mmol, 854 mg) in EtOH (450 mL) was passed through a Pt/C₅% column in an H-Cube equipment (mode: Full). Then the solution was concentrated under reduced pressure to yield tert-butyl 4-(4-amino-2-chlorophenyl)piperazine-1-carboxylate (2.46 mmol, 766 mg, 98%). The product was used without further purification.

LC (Zorbax SB-C₁₈, 3.5 μm, 4.6×30 mm Column) RT=2.37 min; MS m/z ES⁺=312.

tert-Butyl 4-(2-chloro-4-(picolinamido)phenyl)piperazine-1-carboxylate

According to Scheme 5 Step 3: Picolinoyl chloride hydrochloride (3.68 mmol, 656 mg) and Et₃N (7.37 mmol, 1.03 mL) were added to a solution of tert-butyl 4-(4-amino-2-chlorophenyl)piperazine-1-carboxylate (2.46 mmol, 766 mg) in DCM (40 mL) at 0° C. The reaction mixture was stirred at room temperature for 1 hour. The organic phase was washed with a saturated solution of NaHCO₃. The aqueous phase was extracted with AcOEt. The organic phase was washed with brine, was dried over Na₂SO₄, was filtered and was concentrated under reduced pressure to afford tert-butyl 4-(2-chloro-4-(picolinamido)phenyl)piperazine-1-carboxylate (2.46 mmol, 1.02 g, 100%).

LC (Zorbax SB-C₁₈, 3.5 μm, 4.6×30 mm Column) RT=3.19 min; MS m/z ES⁺=417.

N-(3-Chloro-4-(piperazin-1-yl)phenyl)picolinamide

According to Scheme 5 Step 4: HCl 4 M in dioxane (12.3 mmol, 3.07 mL) was added to a solution of tert-butyl 4-(2-chloro-4-(picolinamido)phenyl)piperazine-1-carboxylate (2.46 mmol, 1.02 g) in DCM (10 mL). The reaction mixture was stirred at room temperature overnight. After evaporation, DCM was added and then a NaOH 1 M solution. The aqueous phase was extracted with DCM. The organic phase was washed with brine, was dried over MgSO₄, was filtered and was concentrated under reduced pressure. The crude product was purified by flash chromatography over silica gel using cyclohexane/AcOEt (60:40) as eluent to afford N-(3-chloro-4-(piperazin-1-yl)phenyl)picolinamide (0.97 mmol, 308 mg, 40%) as an orange solid.

LC (Zorbax SB-C₁₈, 3.5 μm, 4.6×30 mm Column) RT=1.41 min; MS m/z ES⁺=317.

N-(3-Chloro-4-(4-propionylpiperazin-1-yl)phenyl)picolinamide

According to Scheme 5 Step 5 Method A: A solution of N-(3-chloro-4-(piperazin-1-yl)phenyl)picolinamide (0.19 mmol, 60 mg), propionic acid (0.19 mmol, 14 μL), EDCI.HCl (0.28 mmol, 54 mg), Et₃N (0.38 mmol, 53 μL) and of hydroxybenzotriazole (0.21 mmol, 32 mg) in DCM (5 mL) was stirred at room temperature for 1 day. The solution was quenched with water. The aqueous phase was extracted with DCM. The organic phase was washed with brine, was dried over Na₂SO₄, was filtered and was concentrated under reduced pressure. The solid was triturated with water and finally with iPr₂O to afford N-(3-chloro-4-(4-propionylpiperazin-1-yl)phenyl)picolinamide (0.14 mmol, 51 mg, 72%) as a yellow solid.

M.p.: 176-179° C.;

LC (Zorbax SB-C₁₈, 3.5 μm, 4.6×30 mm Column) RT=2.35 min; MS m/z ES⁺=373.

Example 8 N-(4-(4-Benzylpiperazin-1-yl)-3-chlorophenyl)picolinamide (Final Compound 4-5)

According to Scheme 5 Step 5 Method B: A suspension of (bromomethyl)benzene (0.61 mmol, 74 μL), N-(3-chloro-4-(piperazin-1-yl)phenyl)picolinamide (0.51 mmol, 161 mg) and of K₂CO₃ (0.51 mmol, 70 mg) in ACN (3 mL) was stirred at 80° C. for 30 minutes. After evaporation of the solvent, water and AcOEt were added. The aqueous phase was extracted with AcOEt. The organic phase was washed with brine, was dried over Na₂SO₄, was filtered and was concentrated under reduced pressure. The crude product was purified by flash chromatography over silica gel using DCM/AcOEt (80:20) as eluent and finally crystallized in pentane to obtain N-(4-(4-benzylpiperazin-1-yl)-3-chlorophenyl)picolinamide (0.98 mmol, 40 mg, 20%) as a white solid.

M.p.: 92-94° C.;

LC (Zorbax SB-C₁₈, 3.5 μm, 4.6×30 mm Column) RT=1.99 min; MS m/z ES⁺=407.

The compounds in the following Tables have been synthesized according to the same method as previous examples 1 to 5, as denoted in the column denoted as “Exp. nr”. The compounds denoted with the asterisk have been exemplified in the Examples.

TABLE 1 Compounds prepared according to the Examples.

Co.nr. Exp nr.

1-1 2

1-2 2

1-3 2

1-4 1

1-5 2

TABLE 2 Compounds prepared according to the Examples.

Co.nr. Exp nr.

B¹ B² 2-1  1*

H Me 2-2 3

H

2-3  2*

H Me 2-4 2

H Me 2-5 1

H Me 2-6 1

H CF₃ 2-7 3

H

2-8 3

H CH₂CH₂CH₂Ph 2-9  3*

H

 2-10 3

H

 2-11 3

H

 2-12 3

H

 2-13 1

H Me  2-14 1

F Me  2-15 3

H

 2-16 2

H Me  2-17 1

F Me  2-18 1

F Me

TABLE 3 Compounds prepared according to the Examples.

Co.nr. Exp nr.

B¹ B² 3-1 4

H

3-2 1

Cl

3-3 2

Cl

3-4 1

Cl

3-5 4

Cl

3-6 4

Cl

3-7 4

Cl

3-8 1

Cl

3-9  5*

OMe

 3-10 1

H —CF₃  3-11  4*

Cl

 3-12 4

Cl

 3-13 4

Cl

 3-14 4

Cl

 3-15 4

Cl

 3-16 4

Cl

TABLE 4 Compounds prepared according to the Examples.

Co.nr. Exp nr.

B¹

4-1 1 

Cl

4-2 6*

Cl

4-3 7*

Cl

4-4 7 

Cl

4-5 8*

Cl

Physico-Chemical Data LCMS-Methods:

LCMS were recorded on a Waters Micromass ZQ 2996 system by the following conditions:

Reversed phase HPLC was carried out on an Zorbax SB-C18 cartridge (1.8 μm, 4.6×30 mm) from Agilent, with a flow rate of 1.5 ml/min. The gradient conditions used are: 90% A (water+0.05% of formic acid), 10% B (acetonitrile+0.05% of formic acid) to 100% B at 3.5 minutes, kept till 3.7 minutes and equilibrated to initial conditions at 3.8 minutes until 4.5 minutes. Injection volume 5-20 μL. ES MS detector was used, acquiring both in positive and negative ionization modes. Cone voltage was 30 V for both positive and negative ionization modes.

All mass spectra were taken under electrospray ionisation (ESI) methods.

TABLE 5 Physico-chemical data for some compounds (nd = not determined). Melting MW RT Co. Nr point (° C.) (theor) [MH⁺] (min) Physical form 1-1 nd 255.10 256 2.49 White solid 1-2 139-140 237.70 238 4.23 White solid 1-3 89.8-91.3 232.67 233 3.80 White solid 1-4 74-75 216.21 217 2.37 Yellow solid 1-5 138-140 220.65 221 2.24 White solid 2-1   139-140.5 233.29 234 3.80 White solid 2-2 148-149 339.32 340 2.42 White solid 2-3 nd 228.25 229 3.94 Orange oil 2-4 87-89 248.30 249 3.85 Orange solid 2-5 53-57 234.27 235 2.20 White solid 2-6 79.5-80.5 282.22 283 2.80 Yellow solid 2-7 139-140 366.80 367 2.81 Yellow solid 2-8 49-51 332.39 333 3.23 White solid 2-9 136-137 362.38 363 2.67 Yellow solid  2-10 114.5-115.5 362.38 363 2.63 White solid  2-11 118-121 350.34 351 2.64 Yellow solid  2-12 nd 366.79 367 2.74 Yellow solid  2-13  98-101 232.23 233 2.16 Yellow solid  2-14 nd 246.24 247 2.30 Brown solid  2-15  98-101 350.34 351 2.65 Yellow solid  2-16 119-122 229.23 230 1.91 White solid  2-17 124-125 264.23 265 2.39 White solid  2-18 103-105 252.26 253 2.19 White solid 3-2 195-197 326.74 327 2.15 White solid 3-3 142-150 346.79 347 2.12 White solid 3-4 154 332.76 333 2.10 Yellow solid 3-5 254-260 325.75 326 2.57 Beige solid 3-6 102-104 360.74 361 3.03 Beige solid 3-7  99-101 359.21 360 3.16 White solid 3-8 92-94 393.75 394 3.02 White solid 3-9 203-205 322.32 323 1.87 Beige solid  3-11 91.5-93.5 359.21 360 3.35 White solid  3-12 78-80 342.75 343 3.17 Yellow solid  3-13 104-105 342.75 343 3.10 White solid  3-14 133-135 359.21 360 3.32 White solid  3-15 157-159 349.77 350 2.90 Beige solid  3-16 223-228 350.76 351 2.06 Beige solid 4-2 156-158 386.88 387 2.50 Beige solid 4-3 176-179 372.85 373 2.35 Yellow solid 4-4 161-163 420.89 421 2.68 Yellow solid 4-5 92-94 406.91 407 1.99 White solid

Pharmacology

The compounds provided in the present invention are positive allosteric modulators of mGluR4. As such, these compounds do not appear to bind to the orthosteric glutamate recognition site, and do not activate the mGluR4 by themselves. Instead, the response of mGluR4 to a concentration of glutamate or mGluR4 agonist is increased when compounds of Formula I, I-a-d are present. Compounds of Formula I, I-a-d are expected to have their effect at mGluR4 by virtue of their ability to enhance the function of the receptor.

mGluR4 Assay on HEK-Expressing Human mGluR4

The compounds of the present invention are positive allosteric modulators of mGluR4 receptor. Their activity was examined on recombinant human mGluR4a receptors by detecting changes in intracellular Ca²⁺ concentration, using the fluorescent Ca²⁺-sensitive dye Fluo4-(AM) and a Fluorometric Imaging Plate Reader (FLIPR, Molecular Devices, Sunnyvale, Calif.)

Transfection and Cell culture

The cDNA encoding the human metabotropic glutamate receptor (hmGluR4), (accession number NM_(—)000841.1, NCBI Nucleotide database browser), was subcloned into an expression vector containing also the hygromycin resistance gene. In parallel, the cDNA encoding a G protein allowing redirection of the activation signal to intracellular calcium flux was subcloned into a different expression vector containing also the puromycin resistance gene. Transfection of both these vectors into HEK293 cells with PolyFect reagent (Qiagen) according to supplier's protocol, and hygromycin and puromycin treatment allowed selection of antibiotic resistant cells which had integrated stably one or more copies of the plasmids. Positive cellular clones expressing hmGluR4 were identified in a functional assay measuring changes in calcium fluxes in in response to glutamate or selective known mGluR4 orthosteric agonists and antagonists

HEK-293 cells expressing hmGluR4 were maintained in media containing DMEM, dialyzed Fetal Calf Serum (10%), Glutamax™ (2 mM), Penicillin (100 units/ml), Streptomycin (100 μg/ml), Geneticin (100 μg/ml) and Hygromycin-B (40 μg/ml) and puromycin (1 μg/ml) at 37° C./5% CO₂.

Fluorescent Cell Based-Ca²⁺ Mobilization Assay

Human mGluR4 HEK-293 cells were plated out 24 hours prior to FLIPR³⁸⁴ assay in black-walled, clear-bottomed, poly-L-ornithine-coated 384-well plates at a density of 25,000 cells/well in a glutamine/glutamate free DMEM medium containing foetal bovine serum (10%), penicillin (100 units/ml) and streptomycin (100 μg/ml) at 37° C./5% CO₂.

On the day of the assay, the medium was aspirated and the cells were loaded with a 3 μM solution of Fluo4-AM (LuBioScience, Lucerne, Switzerland) in 0.03% pluronic acid. After 1 hour at 37° C./5% CO₂, the non incorporated dye was removed by washing cell plate with the assay buffer and the cells were left in the dark at room temperature for six hours before testing. All assays were performed in a pH 7.4 buffered-solution containing 20 mM HEPES, 143 mM NaCl, 6 mM KCl, 1 mM MgSO₄, 1 mM CaCl₂, 0.125 mM sulfapyrazone, 0.1% glucose.

After 10 s of basal fluorescence recording, various concentrations of the compounds of the invention were added to the cells. Changes in fluorescence levels were first monitored for 180 s in order to detect any agonist activity of the compounds. Then the cells were stimulated by an EC₂₅ glutamate concentration for an additional 110 s in order to measure enhancing activities of the compounds of the invention. EC₂₅ glutamate concentration is the concentration giving 25% of the maximal glutamate response.

The concentration-response curves of representative compounds of the present invention were generated using the Prism GraphPad software (Graph Pad Inc, San Diego, USA). The curves were fitted to a four-parameter logistic equation:

(Y=Bottom+(Top−Bottom)/(1+10̂((Log EC ₅₀ −X)*Hill Slope)

allowing determination of EC₅₀ values.

The Table 6 below represents the mean EC₅₀ obtained from at least three independent experiments of selected molecules performed in duplicate.

TABLE 6 Activity data for selected compounds Compound n° Ca²⁺ Flux* 2-4 ++ 1-2 ++ 1-3 +++ 2-5 ++ 2-6 ++ 2-7 ++ 2-8 ++ 2-9 ++  2-10 ++  2-11 ++  2-12 ++  2-13 ++  2-14 +++ 1-5 ++  2-15 ++  2-16 ++  2-17 ++ 3-2 +++  2-18 ++ 3-4 ++ 3-5 +++ 3-8 ++ 4-3 ++ 4-4 ++  3-15 +++ 4-5 ++ *Table legend: (+): EC₅₀ > 10 μM (++): 1 μM < EC₅₀ < 10 μM (+++): EC₅₀ < 1 μM

The results in Table 6 demonstrate that the compounds described in the present invention are positive allosteric modulators of human mGluR4 receptors. These compounds don't have activity by themselves but they rather increase the functional activity and/or maximal efficacy of glutamate or mGluR4 agonist.

Thus, the positive allosteric modulators provided in the present invention are expected to increase the effectiveness of glutamate or mGluR4 agonists at mGluR4 receptor. Therefore, these positive allosteric modulators are expected to be useful for treatment of various neurological and psychiatric disorders associated with glutamate dysfunction described to be treated herein and others that can be treated by such positive allosteric modulators.

Formulation Examples

Typical examples of recipes for the formulation of the invention are as follows:

1. Tablets

Active ingredient 5 to 50 mg Di-calcium phosphate 20 mg Lactose 30 mg Talcum 10 mg Magnesium stearate 5 mg Potato starch ad 200 mg

In this Example, active ingredient can be replaced by the same amount of any of the compounds according to the present invention, in particular by the same amount of any of the exemplified compounds.

2. Suspension

An aqueous suspension is prepared for oral administration so that each 1 milliliter contains 1 to 5 mg of one of the active compounds, 50 mg of sodium carboxymethyl cellulose, 1 mg of sodium benzoate, 500 mg of sorbitol and water ad 1 ml.

3. Injectable

A parenteral composition is prepared by stirring 1.5% by weight of active ingredient of the invention in 10% by volume propylene glycol and water.

4. Ointment

Active ingredient 5 to 1000 mg Stearyl alcohol 3 g Lanoline 5 g White petroleum 15 g Water ad 100 g

In this Example, active ingredient can be replaced with the same amount of any of the compounds according to the present invention, in particular by the same amount of any of the exemplified compounds.

Reasonable variations are not to be regarded as a departure from the scope of the invention. It will be obvious that the thus described invention may be varied in many ways by those skilled in the art. 

1. A compound having the Formula (I-b),

a pharmaceutically acceptable acid or base addition salt thereof, a stereochemically isomeric form thereof and an N-oxide form thereof, wherein: X¹ is N and X², X³ and X⁴ are each independently selected from the group of C, N, O, S and C═C representing a 5 or 6 membered heteroaryl ring which may further be substituted by 1 to 3 radicals A^(m); m is an integer ranging from 1 to 3; A^(m) radicals are each independently selected from the group of hydrogen, halogen, —CN, —OH, —NO₂, —CF₃, —SH, —NH₂ and an optionally substituted radical selected from the group of —(C₁-C₆)alkyl, —(C₁-C₆)alkylhalo, —(C₃-C₇)cycloalkyl, —(C₁-C₆)alkylcyano, —(C₁-C₆)alkylheteroaryl, —(C₁-C₆)alkylaryl, aryl, heteroaryl, heterocycle, —(C₀-C₆)alkyl-OR¹, —O—(C₂-C₆)alkyl-OR¹, —(C₃-C₂)cycloalkyl-(C₁-C₆)alkyl, —O—(C₃-C₂)cycloalkyl-(C₁-C₆)alkyl, —(C₁-C₆)alkylhalo-OR¹, —(C₁-C₆)alkylhalo-NR¹R², —(C₀-C₆)alkyl-S—R¹, —O—(C₂-C₆)alkyl-S—R¹, —(C₀-C₆)alkyl-S(═O)—R¹, —O—(C₁-C₆)alkyl-S(═O)—R¹, —(C₀-C₆)alkyl-S(═O)₂—R¹, —O—(C₁-C₆)alkyl-S(═O)₂—R¹, —O—(C₂-C₆)alkyl-NR¹R², —(C₀-C₆)alkyl-S(═O)₂NR¹R², —O—(C₁-C₆)alkyl-S(═O)₂NR¹R², —O—(C₂-C₆)alkyl-NR¹—S(═O)₂R², —(C₀-C₆)alkyl-C(═O)—NR¹R², —O—(C₁-C₆)alkyl-C(═O)—NR¹R², —O—(C₂-C₆)alkyl-NR¹C(═O)—R², —(C₀-C₆)alkyl-OC(═O)—R¹, —O—(C₂-C₆)alkyl-OC(═O)—R¹, —(C₀-C₆)alkyl-C(═O)—OR¹, —O—(C₁-C₆)alkyl-C(═O)—OR¹, —(C₀-C₆)alkyl-C(═O)—R¹, —O—(C₁-C₆)alkyl-C(═O)—R¹, —(C₀-C₆)alkyl-O—C(═O)—NR¹R², and —O—(C₂-C₆)alkyl-NR¹—C(═O)—NR²R³; R¹, R², R³ and R⁴ are each independently hydrogen or an optionally substituted radical selected from the group of —(C₁-C₆)alkylhalo, —(C₁-C₆)alkyl, —(C₁-C₆)alkylcyano, —(C₃-C₇)cycloalkyl, —(C₄-C₁₀)alkylcycloalkyl, heteroaryl, —(C₁-C₆)alkylheteroaryl, aryl, heterocycle and —(C₁-C₆)alkylaryl; B¹ is selected from the group of halogen, —CN, —OH, —NO₂, —CF₃, —SH, —NH₂ and an optionally substituted radical selected from the group of —(C₁-C₆)alkyl, —(C₁-C₆)alkylhalo, —(C₃-C₇)cycloalkyl, —(C₁-C₆)alkylcyano, —(C₁-C₆)alkylheteroaryl, —(C₁-C₆)alkylaryl, aryl, heteroaryl, heterocycle, —(C₀-C₆)alkyl-OR⁵, —O—(C₂-C₆)alkyl-OR⁵, —NR⁵(C₂-C₆)alkyl-OR⁶, —(C₃-C₇)cycloalkyl-(C₁-C₆)alkyl, —O—(C₃-C₇)cycloalkyl-(C₁-C₆)alkyl, —NR⁵—(C₃-C₇)cycloalkyl-(C₁-C₆)alkyl, —(C₁-C₆)alkylhalo-OR⁵, —(C₁-C₆)alkylhalo-NR⁵R⁶, —(C₀-C₆)alkyl-S—R⁵, —O—(C₂-C₆)alkyl-S—R⁵, —NR⁵—(C₂-C₆)alkyl-S—R⁶, —(C₀-C₆)alkyl-S(═O)—R⁵, —O—(C₁-C₆)alkyl-S(═O)—R⁵, —NR⁵—(C₁-C₆)alkyl-S(═O)—R⁶, —(C₀-C₆)alkyl-S(═O)₂—R⁵, —O—(C₁-C₆)alkyl-S(═O)₂—R⁵, —NR⁵—(C₁-C₆)alkyl-S(═O)₂—R⁶, —(C₀-C₆)alkyl-NR⁵R⁶, —O—(C₂-C₆)alkyl-NR⁵R⁶, —NR⁵—(C₂-C₆)alkyl-NR⁶R⁷, —(C₀-C₆)alkyl-S(═O)₂NR⁵R⁶, —O—(C₁-C₆)alkyl-S(═O)₂NR⁵R⁶, —NR⁵—(C₁-C₆)alkyl-S(═O)₂NR⁶R⁷, —(C₀-C₆)alkyl-NR⁵—S(═O)₂R⁶, —O—(C₂-C₆)alkyl-NR⁵—S(═O)₂R⁶, —NR⁵—(C₂-C₆)alkyl-NR⁶—S(═O)₂R⁷, —(C₀-C₆)alkyl-C(═O)—NR⁵R⁶, —O—(C₁-C₆)alkyl-C(═O)—NR⁵R⁶, —NR⁵—(C₁-C₆)alkyl-C(═O)—NR⁶R⁷, —(C₀-C₆)alkyl-NR⁵C(═O)—R⁶, —O—(C₂-C₆)alkyl-NR⁵C(═O)—R⁶, —NR⁵—(C₂-C₆)alkyl-NR⁶C(═O)—R⁷, —(C₀-C₆)alkyl-OC(═O)—R⁵, —O—(C₂-C₆)alkyl-OC(═O)—R⁵, —NR⁵—(C₂-C₆)alkyl-OC(═O)—R⁶, —(C₀-C₆)alkyl-C(═O)—OR⁵, —O—(C₁-C₆)alkyl-C(═O)—OR⁵, —NR⁵—(C₁-C₆)alkyl-C(═O)—OR⁶, —(C₀-C₆)alkyl-C(═O)—R⁵, —O—(C₁-C₆)alkyl-C(═O)—R⁵, —NR⁵—(C₁-C₆)alkyl-C(═O)—R⁶, —(C₀-C₆)alkyl-NR⁵—C(═O)—OR⁶, —(C₀-C₆)alkyl-O—C(═O)—NR⁵R⁶, —(C₀-C₆)alkyl-NR⁵—C(═NR⁶)—NR⁷R⁸, —(C₀-C₆)alkyl-NR⁵—C(═O)—NR⁶R⁷, —O—(C₂-C₆)alkyl-NR⁵—C(═O)—NR⁶R⁷, —NR⁵—(C₂-C₆)alkyl-NR⁶—C(═O)—NR⁷R⁸ and —(C₀-C₆)alkyl-NR⁵—C(═S)—NR⁶R⁷; B² is an optionally substituted aryl or heteroaryl; R⁵, R⁶, R⁷ and R⁸ are each independently hydrogen or an optionally substituted radical selected from the group of —(C₁-C₆)alkylhalo, —(C₁-C₆)alkyl, —(C₁-C₆)alkylcyano, —(C₃-C₇)cycloalkyl, —(C₄-C₁₀)alkylcycloalkyl, heteroaryl, —(C₁-C₆)alkylheteroaryl, aryl, heterocycle and —(C₁-C₆)alkylaryl; Any two radicals of R(R⁵, R⁶, R⁷ or R⁸) may be taken together to form an optionally substituted 3 to 10 membered carbocyclic or heterocyclic ring.
 2. A compound according to claim 1, which can exist as optical isomers, wherein said compound is either the racemic mixture or one or both of the individual optical isomers.
 3. A compound according to claim 1, wherein said compound is: N-(3-Chloro-4-(pyrimidin-2-yloxy)phenyl)picolinamide or a pharmaceutically acceptable acid or base addition salt thereof, a stereochemically isomeric form thereof and an N-oxide form thereof.
 4. A pharmaceutical composition comprising a therapeutically effective amount of a compound according to claims 1 to 3 and a pharmaceutically acceptable carrier and/or excipient.
 5. A method of treating or preventing a condition in a mammal, including a human, the treatment or prevention of which is affected or facilitated by the neuromodulatory effect of mGluR4 allosteric modulators, comprising administering to a mammal in need of such treatment or prevention, an effective amount of a compound/composition according to claims 1 to
 3. 6. A method of treating or preventing a condition in a mammal, including a human, the treatment or prevention of which is affected or facilitated by the neuromodulatory effect of mGluR4 positive allosteric modulators, comprising administering to a mammal in need of such treatment or prevention, an effective amount of a compound/composition according to claims 1 to
 3. 7. A method useful for treating or preventing central nervous system disorders selected from the group consisting of: addiction, tolerance or dependence, affective disorders, such as depression and anxiety, psychiatric disease such as psychotic disorders, attention-deficit/hyperactivity disorder and bipolar disorder; Parkinson's disease, memory impairment, Alzheimer's disease, dementia, delirium tremens, other forms of neurodegeneration, neurotoxicity, and ischemia, comprising administering to a mammalian patient in need of such treatment an effective amount of a compound/composition according to claims 1 to
 3. 8. A method useful for treating or preventing central nervous system disorders selected from the group consisting of Parkinson's disease and movement disorders such as bradykinesia, rigidity, dystonia, drug-induced parkinsonism, dyskinesia, tardive dyskinesia, L-DOPA-induced dyskinesia, dopamine agonist-induced dyskinesia, hyperkinetic movement disorders, Gilles de la Tourette syndrome, resting tremor, action tremor, akinesia, akinetic-rigid syndrome, akathisia, athetosis, asterixis, tics, postural instability, postencephalitic parkinsonism, muscle rigidity, chorea and choreaform movements, spasticity, myoclonus, hemiballismus, progressive supranuclear palsy, restless legs syndrome, periodic limb movement disorder, comprising administering to a mammalian patient in need of such treatment an effective amount of a compound/composition according to claims 1 to
 3. 9. A method useful for treating or preventing central nervous system disorders selected from the group consisting of cognitive disorders: delirium, substance-induced persisting delirium, dementia, dementia due to HIV disease, dementia due to Huntington's disease, dementia due to Parkinson's disease, Parkinsonian-ALS demential complex, dementia of the Alzheimer's type, substance-induced persisting dementia and mild cognitive impairment comprising administering to a mammalian patient in need of such treatment an effective amount of a compound/composition according to claims 1 to
 3. 10. A method useful for treating affective disorders, anxiety, Agoraphobia, Generalized Anxiety Disorder (GAD), Obsessive-Compulsive Disorder (OCD), Panic Disorder, Posttraumatic Stress Disorder (PTSD), Social Phobia, Other Phobias, Substance-Induced Anxiety Disorder, acute stress disorder comprising administering to a mammalian patient in need of such treatment or prevention, an effective amount of a compound/composition according to claims 1 to
 3. 11. A method useful for treating or preventing central nervous system disorders selected from the group consisting of mood disorders: Bipolar Disorders (I & II), Cyclothymic Disorder, Depression, Dysthymic Disorder, Major Depressive Disorder, Substance-Induced Mood Disorder, comprising administering an effective amount of a compound/composition according to claims 1 to
 3. 12. A method useful for treating or preventing neurological disorders selected from the group of neurodegeneration, neurotoxicity or ischemia such as stroke, spinal cord injury, cerebral hypoxia, intracranial hematoma, Parkinson's disease, memory impairment, Alzheimer's disease, dementia, delirium tremens comprising administering to a mammalian patient in need of such treatment or prevention, an effective amount of a compound/composition according to claims 1 to
 3. 13. A method useful for treating or preventing inflammatory central nervous system disorders selected from multiple sclerosis forms such as benign multiple sclerosis, relapsing-remitting multiple sclerosis, secondary progressive multiple sclerosis, primary progressive multiple sclerosis, progressive-relapsing multiple sclerosis, comprising administering an effective amount of a compound/composition according to claims 1 to
 3. 14. A method useful for treating migraine comprising administering an effective amount of a compound/composition according to claims 1 to
 3. 15. A method useful for treating or preventing epilepsy and tremor, temporal lobe epilepsy, epilepsy secondary to another disease or injury e.g., chronic encephalitis, traumatic brain injury, stroke or ischemia comprising administering to a mammal in need of such treatment or prevention, an effective amount of a compound/composition according to claims 1 to
 3. 16. A method useful for treating or preventing inflammation and/or neurodegeneration resulting from traumatic brain injury, stroke, ischemia, spinal cord injury, cerebral hypoxia or intracranial hematoma, comprising administering to a mammal in need of such treatment an effective amount of a compound/composition according to claims 1 to
 3. 17. A method useful for treating or preventing sensory, motor or cognitive symptoms resulting from traumatic brain injury, stroke, ischemia, spinal cord injury, cerebral hypoxia or intracranial hematoma, comprising administering to a mammal in need of such treatment or prevention, an effective amount of a compound/composition according to claims 1 to
 3. 18. A method useful for treating medulloblastomas comprising administering an effective amount of a compound/composition according to claims 1 to
 3. 19. A method useful for treating or preventing inflammatory or neuropathic pain comprising administering to a mammalian patient in need of such treatment an effective amount of a compound/composition according to claims 1 to
 3. 20. A method useful for treating, or preventing, ameliorating, controlling or reducing the risk of various metabolic disorders associated with glutamate dysfunction comprising administering to a mammalian patient in need of such treatment an effective amount of a compound/composition according to claims 1 to
 3. 21. A method useful for treating or preventing type 2 diabetes comprising administering to a mammalian patient in need of such treatment an effective amount of a compound/composition according to claims 1 to
 3. 22. A method useful for treating or preventing diseases or disorders of the retina, retinal degeneration or macular degeneration, comprising administering to a mammalian patient in need of such treatment an effective amount of a compound/composition according to claims 1 to
 3. 23. A method useful for treating or preventing diseases or disorders of the gastrointestinal tract including gastro-esophageal reflux disease (GERD), lower esophageal sphincter diseases or disorders, diseases of gastrointestinal motility, colitis, Crohn's disease or irritable bowel syndrome (IBS), comprising administering to a mammalian patient in need of such treatment an effective amount of a compound/composition according to claims 1 to
 3. 24. Use of a compound according to claims 1 to 3, or a pharmaceutically acceptable salt thereof, in the provision of a medicament for treating or preventing a disorder or disease by administering an effective amount of an mGluR4 positive allosteric modulating compound.
 25. Use of a compound according to claims 1 to 3 to prepare a tracer for imaging a metabotropic glutamate receptor.
 26. Use of a compound according to claims 1 to 3 as a taste agent, flavour agent, flavour enhancing agent or a food or beverage additive. 